Earlier quoted context omitted.
It appears in places where that are neither personal websites nor blogs, and that are places where professionals conduct work. For instance: The act of searching the Arch Linux wiki produces a picture of the anime girl. (Should I just not use Arch professionally?)
I don't see what's so offensive about it. If it had huge boobs or something that would be one thing, but it's just a regular mascot character. Out of all the "necessary evils" that get inserted to keep a service above water, that anime girl image is the least offensive one I can think of. It's still completely normalized to show ads for porn on sites like youtube. Captchas are an insult, with the "photo challenge" ty…
It does this in ways that a boring corpo captcha or Cloudflare prompt do not, so it's presence of this artwork more than it is the temporary time-wasting impediment that seems to do it.
People have irrational reactions to things sometimes, and I am people.