Danbooru is like a library of anime (often sexual) art. It is all tagged. Are you angry at your local library for lending books that are copyrighted? I don't think so. If not for Danbooru, I wouldn't know about many good artists. I came upon my all-time favorite artist on Konachan in 2011 (I used to browse E-Shuushuu and other websites, not Danbooru). Back then, Pixiv was 100% in Japanese and translators were nearly useless. With anime and manga things are different, because they are media you have to pay for. Paid rewards are banned on Danbooru since 2020. Art on Twitter etc is free and Danbooru always provides links for sources.