You see, there's a huge difference between how much you win and how much you understand the game. Points and ranking are a good indicator of how much you win, but they do jack shit when it comes to reflecting your game knowledge. Here's a little rundown of the correlation between leagues and understanding of the game:
Bronze: I know what some of the units do.
Silver: I know what a build order is.
Gold: I have a build order for most of the matchups.
Platinum (not stuck-in-platinum-because-stupid-system-won't-promote-me but actual platinum): I have played through my build order more than twenty times.
Diamond: Anything above that.
If you are at all familiar with Brood War and iCCup rankings, here's what it would look like:
Bronze: I play B.net custom games. I can give the computer a good fight.
Silver: I play Fastest Possible Map Ever.
Gold: I play BGH and some low maps. I know who Boxer is.
Platinum: Computer (E) rank
Low diamond (~300): D-
Mid diamond (~600): D
High diamond (~900): D+ through C
Top diamond (~1200): B
You see, a strange phenomenon exists since SC2 is such a new game. It's that you can do almost whatever you want and make it work. There's no such thing as standard play, standard timings, and standard defenses. What this means is that 1 base allins are extremely potent, especially at lower levels, and even at what you might consider high levels as well. That means that even at the 900 point diamond range, there exist an abundance of players who simply just know how to 4gate allin or marine/hellion/tank allin. They just know one build per matchup, practice it to death, and the go on the ladder and win because people don't know how to respond. Does this mean they know how to win? Of course. But does it mean they know anything about the game? Not at all. They are the equivalent of a D+ high player on iCCup. They don't know anything about timings, their opponents' production capabilities, etc. beyond the first eight minutes of the game. I am not complaining about this, mind you. On the contrary, I find that the existence of these people makes my laddering experience much more rewarding since I know that all I have to do is defend one stupid allin and then the game is mine.
On the other hand, there exist another group of 900 point diamond leaguers who legitimately understand the game. They have a solid build order, solid mechanics, and a solid understanding of the game. They could be considered C level iCCup players, maybe even C+. But, every so often, they lose to the aforementioned group of diamond leaguers just because they don't know how to respond, because they just don't have the experience with the game to deal with every single crazy build thrown at them. As time goes on, these diamond players will slowly improve, while the aforementioned group will stagnate.
One of my biggest pet peeves in the Starcraft 2 strategy forums is when someone contradicts a legitimately good player. You may think, "oh TL elitist blah blah blah," but I assure you I have a very good reason for this. Because, while the lesser player may offer some valuable insight and a game-changing perspective (this has actually happened its fair share of times in the past - mutalisk magic box is just one of the many examples, though the credit really should go to Zelniq, a very good player, who first posted about it), 99% of the time, the lesser player will be wrong and the legitimately good player will be right. This is because the game is still developing. Everyone, from the bronze league all the way up to the very top, is still learning. Their play is still changing. Starcraft is an incredibly streaky game - you can only go so far with a build order or playstyle until it stops working. Then you start losing and are forced to change it up to deal with new playstyles and stronger opponents. But whereas the lesser player may have experienced this two or three times, the top players have dealt with this too many times to count. They know what works and what doesn't because they have been there and tried it. IdrA is a prime example of this. As much as people love to bash him for being one-dimensional and using the same build order every game, this cannot be further from the truth. He may use the same opening every game because he wants to find a "standard," a universal opening that can deal with every kind of cheese while still maintaining a solid economy, but he still has to change his game and respond to every type of situation thrown at him. In this case, he has grown much more than all the players who learn one build order per matchup or even two, three, or more - he's much more flexible because he's learning how to adapt. That's why you see him so high on the Korean ladder, and with an insane win rate on the US server. Because he understands the game more than almost anyone else at the moment.
So why am I telling you this? I just want you to know that whenever someone says he's a 800 or 900 point diamond player before giving advice, he's not saying anything about whether or not he knows anything about the game. It's actually very likely that he doesn't know what he's talking about, which would be a typical case of the blind leading the blind. And yes, it's entirely possible to get into "high diamond" by rehearsing one allin build over and over again. Actually, that's probably the easiest way to do so. But eventually, you're going to have to change it up, you're going to actually have to understand the game.
Note: I'm not trying to discourage sharing your opinions. In fact, some of the greatest innovations come from Gold or low-Diamond league players who theorycraft and actually explore the game. Just give respect where it is due. Whenever IdrA or Sheth or CatZ or HuK or Drewbie or Qxc or Jinro or Nazgul or MorroW, etc. posts, even if it contradicts what you're saying, they're probably right. Even if you're a 900 point diamond player.
EDIT: It seems like a lot of you are missing the implications of this thread.
First, regardless of points, there are two types of players. Players who want to win and players who want to better understand the game. I am saying that this exists even up to what many people consider to be "high diamond," while still existing in lower leagues. The problem comes when people with a certain number of points start using that as evidence for their advice, even though that says nothing about their understanding of the game.
Second, people like Qxc, HuK, Sheth, pretty much all of the top players frequent TL. They actually visit it a lot. But they don't post a lot. You might be wondering why they don't provide insight and contribute to discussions. From an interview with Qxc:
TL: Just curious, how much do you read TL?
qxc: I skim the forums occasionally, but tend not to post as most of the stuff actually regarding the game has a lot of … garbage? Dunno. Just a lot of people theorycrafting. Not actually very useful.
TL: Well, what do you think we could do to encourage more high level discussion that you might consider participating in?
qxc: Have invite only topics. For example, create a TvZ discussion thread and only allow top tier Terrans and Zergs to post in it. Assuming people actually participated, it could be pretty interesting. It’s tough to defend a point when I’ve got bronze players telling me what I’m saying is wrong every other line.
qxc: I skim the forums occasionally, but tend not to post as most of the stuff actually regarding the game has a lot of … garbage? Dunno. Just a lot of people theorycrafting. Not actually very useful.
TL: Well, what do you think we could do to encourage more high level discussion that you might consider participating in?
qxc: Have invite only topics. For example, create a TvZ discussion thread and only allow top tier Terrans and Zergs to post in it. Assuming people actually participated, it could be pretty interesting. It’s tough to defend a point when I’ve got bronze players telling me what I’m saying is wrong every other line.
It's all a matter of respect. I don't know, maybe you'd rather have wonderful theorycrafting sessions with random SC2 players, but I'd rather have mine with Qxc. Of course, the suggestion Qxc proposed is not going to happen because the administrators actually do care about how TL is perceived by the general public. They really want it to be accessible and friendly to players of every skill level. But that's not saying that as things are, we can't get people like Qxc to post a little more frequently by showing them a bit more respect.