We think that needs to get done, but somehow our brain takes the wrong turn, so instead of doing it, we try preach and try to explain to others why it would need to get done, so they might do it.
I realized something while I watched a part of some movie while switching between TV channels after my lunch the other day.
The main actor was about to go do some dangerous mission, and the female(his partner) kept telling him not to do it. At one point she asked "Why YOU?! Why is it that of all people YOU need to go do it?!!"
The guy responded: "Because nobody else can."
And that was the end of discussion. He was right.
The fact that nobody's doing the thing you think needs to get done, only proves that they either don't have what it takes to take action, or they don't even SEE what you see - they don't realize it needs to get done.
Maybe you're wrong about the whole thing, maybe it doesn't really need to get done. Even if it was the truth, it doesn't change the point.
If you don't do something, regardless of wether it's the right or wrong thing to do (by some absolute standard) the fact is that you believe it should be done, and the more you put it off the more frustrated you'll get, the more you'll hate yourself for not acting. WHY IS NOBODY DOING ANYTHING?!
Well, at this particular point in time, you're alone and the sole soul who can make a difference.