Or, rather, #3 stated his opinion. What's wrong with that? Some may disagree with it, but so what? If everyone held the same opinion, we'd have threads with one opening post and twelve thousand me too's.
The way I see it, #3 was a jerk about it.
Because instead of saying something like "I don't like that either, it could really ruin the game for me," he said "Everything poster #1 likes is wrong."
You can respect the validity of someone's ideas without agreeing with them, and you can keep an open channel of discussion without condescending.
For #3, there is no discussion, there's just demagoguery. His mind is made up and he just wants to preach his message. There's no reason to post if you're not making a point, you don't need to leave a post just to see your own text on display. It didn't add anything new, and it's impossible to actually talk about the issues raised, it insults those who don't agree, and, basically, is a jerk about it.
Normally, that's fine, but 4e is a touchy subject 'round here. There's a lot of people really invested in this game.

That means that people should take extra care. If that means keepin' your yap shut instead of cracking wise, you should. Take a minute before you post, ask yourself why you need to post it, and then go ahead with it.
And debating with the mods CAN'T be the most productive way to go about getting back into the fray!