Because nobody is starting the thread by warning off people who disagree. We are starting off the thread by warning off people who insult, disparage, and attack Freepers as ignorant, sheeplike, cultists, conspiracy theory whackos, and people making FreeRepublic look bad.
Why can't you see that?
I think somehow you got your butt hurt when it shouldn't be. Plenty of people disagree with certain aspects of Q and there is no problem when they articulate those disagreements. It's when they disrupt, mock, and attack that they become "trolls." This is not a difficult concept.