Yandex reverse image search is very good. I use it more than tineye, bing, or goog. It either gives you the exact matches if it can find them, or else it can infer what is desired and show many similar matches.
I wonder if that's a function of their technology or their database. Google's image search used to be good, but regulations have forced them to cripple it in some ways, and they might have chosen not to surface results in some contexts.
Also, such data collection abilities are generally limited to governments, so it was clear that many of them (US first and foremost) would ask for exclusion of certain individuals, and so forth, and so on, so the public tools were crippled.
Yandex image search does have some facial recognition, but it also seems bit-starved and/or mixed with text search (there's a bigger chance to match if the name and surname is present).
Also, Google is pretty Victorian about porn these days. It's almost like it has a whitelist of “acceptable” porn sites to suit the tastes of potentially angry old ladies.