(As I asked in the other peer comment, but am curious about your reaction as well) Would it change your mind if the OP were doing it as a form of guerrilla advertising for those sites?
Okay so sending graphic/abusive porn in place of referrer tags to every website you visit is just such a disgusting, fucked up thing to do. Like, if you do this you're objectively a bad person.
If you're doing "guerrilla advertising for those sites" - I just think you're a wanker. It's ineffective and silly.
If you're doing "guerrilla advertising for those sites" - I just think you're a wanker. It's ineffective and silly.