But, again, you're not quite talking about the same thing.
After all, you added "disparaging others" and "celebrate when others are dissatisfied". Which is very different thing than simply being positive about something.
But, in the end, it's all about the specific situation. I've so very rarely seen anyone being shouted down who is making an actual, real criticism rather than appeals to popularity, trying to justify their perspective by appealing to the unknown masses. When people have an actual, real criticism, something they can back up with actual, real examples, then generally the conversation will go back and forth, even if the disagreement is strong. Heck, 200+ pages of halfling threads shows that.
There's absolutely nothing wrong with disagreement. What is wrong is unrelentingly negative people who hate every single thing that comes out and repeatedly shout it from the rooftops in an unending stream of negativity.
Give me people who are positive and passionate about the things they like over the hate-watchers who only want to ram their views down everyone's throats any day of the week.