It's not really "making excuses" when I'm pointing out the explicit story, but okay...
Also he's not a whore, he just got separated from the person he loves (not realizing that's what it was because of the aforementioned abusive childhood) and tried to get into relationships, but it never worked because they were never "the same". As in his feelings. There's mention that the last one looked very much like him, implying he had been trying to find someone like him. That's why when they have sex he says "I've been waiting for this for a long time".

He was just mildly surprised and then got into it, went back for more of his own accord and then ended up asking him to date... He'd had a crush on him since high school... The whole "rape" starts with him having a wet dream about him and waking up with an erection after saying his name in his sleep...
If you keep reading you'll see how he reacts when someone is actually trying to rape him and he doesn't want it, the difference is pretty clear. When the other dude is actually attempting to rape him he fights him off until help arrives.
It's another case of the comments seeing him say "wait, stop" or something and immediately saying rape. Guys, people can be overwhelmed too, that doesn't make it rape. What makes it rape is whether or not the person themselves wants it... He was a virgin, he was just overwhelmed. That's like, the whole thing. He comes to terms with his feelings. But he did enjoy the sex and want more.
The story did a very good job at getting across the seme's lack of understanding/his emotional stunting from his bad upbringing. I got the vibe even before that was actually brought up as a plot point. He's just awkward at expressing himself and his jealousy, but he's entirely willing to listen and work on it.