Thank you for putting things like this.
My stance is simple; you become a sex worker (also known as a whore, but for the sake of argument I'll use the more '''''technical'''' term) when you start proactively selling porn. Porn is explicit sexually-orientated material. It is not ecchi, which can and often is highly suggestive, but does not cross the line into being pornography.
It gets blurry with fetish material, which is subjective. Some people can jerk off to the smell of burning rubber. However, if someone is deliberately and consistently making fetish material for an audience that is openly using it for sexual relief, then I'd argue they fall under the category of a sex worker.
My argument in favour of Mozu not counting as a sex worker is very simple; she's never opened a fansly or any equivalent to it, nor does she make money creating pornographic content. Has she made fetish content before? Yes. Briefly, which she later decided to remove. I would prefer if she never had done it in the first place, and if she ever decides to go back to it, I'll drop her like a spitting cobra. But the fact remains she chose to stop making it, even when it was the most successful material she'd ever made. That takes a lot of effort and a lot of backbone. It's not easy to say 'no' to free money, especially when so many other vtubers see nothing wrong with it even as just a 'side hustle', like Filian.
That's really all I have to say on the subject. If I'm wrong and she decides to make a fansly or starts whoring out in skimpy outfits on Twitch or anywhere else like that, or doing creepy erotic ASMR, then I'll take the L without hesitation along with my blackpill. But I maintain that ecchi isn't porn, and that I believe V-Dere to be one of the few groups that seems to be steering away from sex worker content while the rest of the western industry races to appeal to the coomer demographic. That's something I support.