i think there's more good things to say about the art community than bad and hey i have no problem with people who like their neopet drawn as is or with a crazy design. i mean some love the customization and are very detailed with it. a lot of people who are annoying are just young and dont really know any better! as for not getting your half of an art trade, that happens on almost any site where art is exchanged, not just neopets.
my neopets specific pet peeves have to do more with the bc-- the argument of traditional vs. digital, for example. but even then in real life you will find snobs like that. theres a guy that shares a mutual friend w/ me and he is an art major and makes it his point to shit all over my digital art hobby whenever he sees me b/c it's "not art."
tl;dr problem people in the neopets art community are probably either 1. young 2. a douchebag you'd encounter in another art excursion thats not on neopets. if you want to show off your art, i suggest posting on the art chat rather than the pc. art chat moves slower but you are much more likely to receive better comments and people that are more aware about the boundaries of plagiarism/theft.
i find the art community one of the most likable communities on neopets. way better than pcers. there's a couple really nice art guilds i could point out to you if you would like! not sure if youre a guild type.
except gorubeza, watch out for gorubeza, she takes zero criticism even tho her art could seriously be improved, constantly wants art w/o giving any in return even tho her designs are so stupidly intricate, hated anthro designed pets and refused to vote for them (not sure if she still does) and would DEMAND people told her if they voted for her pets in the bc so she could keep track of votes and would harass you via neomail (not sure if she still does this either. p sure she doesnt. i bc sporadically and i havent seen her do this in a while.)