Everyone is entitled to their own subjective opinion on liking or disliking a show or change within in. There are no wrong opinions, just wrong ways to voice them. To call people idiots or accuse them of bitching, or attacking them, or saying you hate them is NOT the right way voice your opinion.

If you can't have a civil debate about it(ie, "I don't understand why people don't like x, I'm fine with it and this is way), then keep your trap shut and don't get involved in the debate at all(exception, if you're using a caustic critic persona and doing it for rule of funny, and said character you're playing is intentionally an asshole, this can be excused. That's called acting. Understand that most internet critics don't really hold many of the extreme views they voice and only do it for the humor. I've done this myself joking around.)

Same goes for objective points in the argument, if you can't admit when you're wrong on a fact or piece of information, again, keep your trap shut. No one likes debating with a brick wall that can't adapt their argument as the conversation goes on.

And finally, don't say things about the creator you can't back up. Keep criticisms to things you can rightfully complain about. like the way they act regarding their profession and work. Regardless of how many people will say otherwise, if they cuss out fans and call people morons for making rightful and well thought out criticisms, that's something you can complain about in a civil fashion.