Annel, it's hard to get anything useful out of your post so far because everybody who made their posts about their opinions obviously thinks they're well founded or they wouldn't have posted them. So just saying "don't post wrong stuff" doesn't help if you don't point out how they're wrong. The best that can do is just make everybody not post because they have no idea what might be wrong, and then they'll never learn what they're wrong about either because nobody will correct them. Either that, or just ignore the warning and plow on ahead anyway, in which case we're back where we started.
It's better to just let people hash it out, as long as it's not spam or just blatantly off topic. It's still gameplay discussion, after all. Fighting games are too complex to boil down things like character strengths and matchups into completely objective answers.