I think what sets deviantArt so apart is that it's a creator's only site.
Most Everyone on there is a creator first and consumer second.
Compared to e.g. Instagram, where people who don't create use it and follow all sorts of content creators, friends and acquaintances.
On DA this feels like it leads to it being an enormous echo chamber
That's what happens on Facebook within groups. Or on Twitter with hashtags, or on reddit with subreds, on Tumblr too within fandoms and niches.
So anything toxic that can happen in an artist community gets amplified by a lot.
Questionable fetish art (I don't believe in kink shaming, but it stops being a fetish when it crosses consent lines) gets traction easily since for anything there's a whole community on dA.
Art trends and styles also get amplified and develop in extremer ways.
A lot of them quickly get considered cringy by the mainstream because you have to be in the bubble yourself to understand it (no judgement for either side intended. It's just like talking in memes to someone who isn't on the internet. They will just not get it, and from their perspective you will probably sound ridiculous.)
Aaaaand since everyone is a creator... Artist envy is a big issue that just breeeeds drama.
And it's worst, when the more toxic parts of the artists community on dA is where a fresh artist starts.
dA IS the starting point for many when it comes to posting their art and engaging with the community, so the dA community rules and etiquette are often the only thing the users know when they set foot on other platforms.
I think that one might be pretty much outdated tho.
I know that back then, my artist peers all had dA accounts way before any social media's.
DA is 20 years old.. Insta for Android merely 9
So yea, when people started migrating from dA to other Plattforms, you could just tell that they came from there a lot of times, from the type of art they made. Which isn't anything bad by itself.
It just then takes a few unsavory people who also exude the dA vibes for people to stereotype.
Also, because of the age, 2000s emo culture "rawr xD" was huuuuge. And since it's such a sealed eco system, it never went away.
Even Tumblr is only 14 (from 2007)
Twitter and reddit are both 15.
And while 5 years don't sound like much, in this context they are a lot.
Sooo yea, factors that contribute to dA's image and stuff:
Da as an echo chamber.
Creators only platform.
Artist envy and Co as breeding ground for toxicity.
It's own language and culture.
dA's age and thus migrations from the site when insta and Co later became relevant.
And dA's age in general.
..... Uhh... Thank you for coming to my Ted talk. I kinda rambled way too much about this