Vtuber or not it seems weird and wrong to make this kinda art of REAL people
I understand your concern, though it should be noted that the avatar still provides a degree of separation between it and the person behind it. Also, while it's true there are vtubers that don't like lewd art of their avatars, there are some that actively request them, so it's not a black and white issue.
That said, Danbooru has not and will never have any restrictions on NSFW vtuber art, especially when it's so popular here. Ethical concerns about the artwork are beyond our scope. If you don't want to see them, try adding virtual_youtuber -rating:g -rating:s to your blacklist. You can also add specific agency names preceded by a tilde (~hololive, for example) in case someone forgot to add the virtual_youtuber tag, though make sure to add the tilde to virtual_youtuber as well.
