A better question should be “is rape actually a crime?” Technically it’s illegal almost everywhere, but in most jurisdictions, the law almost might as well not exist. “Almost” because it does come to court, just very rarely.
On the other hand, engaging in same-sex relationships used to be illegal in most places, but also in most of those places it was pretty rare for anyone to get in trouble for it. Even if a lot of people were grossed out by the idea of it, most didn’t particularly care enough to consider it a “real” crime. Jaywalking is illegal in most of the US, but if you do it nothing will happen unless you’re black (or occasionally, hispanic) and you happen to be unlucky enough to run into a police officer with nothing better to do. Most places have a handful of obscure laws which few people are aware of, and you won’t get in trouble for them unless the police or some government agency with police powers have already arrested you because they’re convinced you did something, but can’t prove anything else.
Rape falls in the category of laws which aren’t treated as important enough to matter - or important enough to either get rid of the law or make the law matter. If something illegal happens and the legal system doesn’t make a sound, is it really a crime? This is separate to whether rape should be a crime, and the answer to that is yes. Obviously there are some small number of assholes who very loudly disagree. Most are wannabe rapists themselves. While making rape legal wouldn’t actually change much in most places, that wouldn’t make rape advocates any less horrible failures of human beings.