HN is pretty good in this respect. Reddit is still decent, though it can definitely lean towards mean. YouTube / app store reviews... forget any chance of respect.
That's quite different from the style of "oh my god what a bunch of fucking idiots these guys are, ha ha ha". It's a cheap, easy way to get some laughs (see: Ted Dziuba) but I'm not really a fan.
It seems to be popular at the moment to laugh at Justin Beiber online and say how much you hate him. But he's the one making millions out of teenage girls...
With this in mind, it would be wise to direct critical feedback privately to the creator. I believe feedback delivered directly and privately is more likely to see the desired change.
Praise in public, criticise in private.