His point was the usage of a preposition when denoting the extreme example. "Your" is still a preposition. You would never say "try your better;" rather, you'd say "try better."
As for the OP, I've long since given up trying to correct every grammatical mistake people make in online environments, let alone in day to day life. Most people just don't really care to speak/write English well, and that's not going to change any bit by me patronizing their small mistakes. But then again, that's why I also tend to end up only talking to people who can write/speak well--it's a lot less of a headache.