In fairness when some invoke the accusation, "You're not a fan or a real fan if you like or don't like________" (fill in the blank) then it smells of a last ditch attempt to silence whoever they're debating/arguing with.
I think a lot of the posters around here are very intelligent--hell it's one of the reasons I hang around, hoping some of it will rub off on me.

But I also think some of us might not give others credit for their perceptiveness and observational skills. Essentially it sometimes seems like we hammer the same thing at each other over and over thinking that eventually it will sink into the other person's brain and they'll finally "get it" as in seeing your side off the argument.
I think of mysrlf as reasnably perceptive. And if I say I don't see something in a film or television show and someone else keeps arguing, "Yes, it's there. What's wrong with you?" that isn't likely to be persuasive with me. Just insisting on something isn't a convincing argument. Often enough it's when someone just says, "I disagree because of this, this and this..." then I'm more likely to think about it and consider whether I should take another look. In the end I may change my mind or I may still not agree, but at least I won't feel like I was browbeaten about it.