Fansubs are way less common than they used to be, because in the last years Crunchyroll's subs were just good enough. People are not waiting for new fansub releases, but go for what's available right now. There's no point doing something that nobody cares about, so no wonder many fansub groups ceased their work. That said, there still are some groups that make fansubs, but very often they base their work on already existing Crunchyroll subs and mostly just apply different typesetting, provide/improve translations for on-screen text, and fix some awkward dialogues/timing. For example in the last season Commie group was releasing The Ghost in the Shell with improved subs, because Amazon subs did not translate on-screen text. As for legality, they're providing releases via torrents, of course it's illegal. I don't know who and from where is supposed to delete your subs. I guess, nyaa could get taken down...