Does Google.com allow anybody to instantly mimic an artist's style? Obviously AI laws haven't been put in place yet - it doesn't mean it's not unethical.
It's always been possible to imitate an artstyle. Nevertheless, they've never gotten IP protection - they're more like trade secrets.
What's notable is "AI users are trying to copy an artist" != "AI has learned from an artist" != "AI has seen the artist's images in the first place". The most popular supposedly stolen-from artist Greg Rutkowski is not in StableDiffusion's training images, even though users are actively trying to copy him, it's a coincidence that it appears to work. Is that unethical?
Also, AI laws (text and data mining exemptions) /have/ been put in place - to make this explicitly legal!
Imitate, not duplicate. Hours of work/talent vs. stealing an artist's work (see: unlicensed) and feeding it into a software program to spit out a slightly different version (complete with watermarks and all)...
(In fact it’s exactly the same; it’s allowed under the same laws and it respects robots.txt.)