Agreed, to an extent. Half the fun here is the skeet matches that ensue when an article from the NY Times is posted. But some folks try to post stuff that claims the aircraft used in 9/11 were remoted controlled, or that Bush knew about the attacks beforehand, stuff like that.
I still don't see what's wrong with that. The moment we say that we won't even consider the possibility that government would do X, then we're providing government with the perfect cover to do X.
And even if somebody is posting something truly ludicrous, there's nothing harmful in that, unless he starts making nasty personal comments to those posters who might disagree with them. Attitudes towards other posters should be curtailed, but not ideas for discussion.