Constructive criticism is useful, especially when it's coming from your peers. Sometimes that criticism comes in the form of a joke, but that doesn't make it less any valuable or well-meaning.
I put people down sometimes, but part of me is always hoping they'll get back up and prove me wrong. If I really hated somebody I wouldn't say anything at all. I'd just let them go on being terrible.
Maybe it's just the way I was raised, but for me, criticism is a form of affection. A love language, even. To me it means that someone cared enough to want you to do better. Someone took time out of their day to tell you something, and if it stung, that only means there's truth in it.
It's not like I hold other artists to a higher standard than my own. There's just the one standard. I think that being an artist and storyteller comes with moral obligations. You can't simply pander to your audience. You can't just give them what they want, you've got to give them what they need. Don't be afraid to lose your audience from time to time.
Anyway, if I have a pet peeve it's this preoccupation some writers have with their wordcounts. I haven't seen it around here, but it tends to happen to in the science fiction genre. Sure, a million words' worth of story is an achievement, but it's not an unqualified achievement if it's all first-draft and it takes you three pages to describe someone climbing out of bed. If a simple fluff-cutting edit can bring your wordcount down to less than a third, that's not anything to be proud of. But I suppose 300,000 words' worth of story doesn't have the same ring to it.