Background Pony #55A0 I'm just here for the e621 comparisons.
But let me start with a word of explanation that no one asked for: I spend a lot of time there, though I categorically refuse to make an account there, because it's just about the only place that has art of certain characters I like, many of them downloaded and reposted from 15+ year old Twitter posts, 20+ year old Geocities pages, and 30+ year old FTP archives that are no longer available anywhere else.
e621's mod staff are Derpibooru-tier bug-eyed kool-ade-drinking woketards. There is a certain artist who stands accused of expressing wrongthink in a private conversation in the form of admitting to an unforgivable lack of enthusiasm for the Pronoun Mafia a few years back and got hounded completely off the Internet under threat of doxing and much worse. This artist drew a cartoon fox girl I think is cute. e621's mods have shoah'd this particular cartoon fox girl. By that I mean they have B& her and all her images due to her creator's "problematic" opinions. If you don't understand, this is e621 we're talking about here. Two thirds of the art is grotesque gay furry shit, starting with cum inflation porn of obese musclebound cartoon bear trannies in diapers fucking each other in the ass with their warty four-foot-long cocks and getting weirder and creepier from there. e621's mods are all about "muh freedums of expressions" when someone points out that they're hosting cartoon images of vore, scat, watersports, guro, torture, cannibalism, and snuff porn, a significant fraction of it "cub" material depicting characters drawn to look like toddlers, i.e., CP that's just barely legal in some countries on the basis of legal technicalities. That's all 1000% A-OK and if you question any part of any of this you're Literally Worse Than Hitler&tm;.
But that cartoon fox girl, she's got to go, because letting people post, look at, comment on, or upvote pictures of non-sexual pictures of a cute cartoon fox is also Literally Worse Than Hitler&tm;. Pointing out the contradiction is, and I think you probably saw this one coming, also Literally Worse Than Hitler&tm;. I despise those people and hope they all get dick cancer.
If Ponybooru has reached a point where it's reasonable to compare them to e621, I can only shake my head. I'm disappointed but I'm not the least bit surprised.