He did apologize. Twice. He apologized the morning after it happened. He didn't remember what he did exactly but after seeing Cináed carry out a person who looked like Yexing, and Cináed beating him up the next morning, he went to apologize to Yexing. Yexing lied and told him he was never in the house so nothing happened. So he let it go. 4 yrs later, current story, at the end of their first night together, Yexing mentioned this not being the first time they slept together as he passed out. Raman thought back and realized the incident 4 years ago was real and that Yexing was the victim. He apologized that morning when he woke up. Yexing had forgiven him already, but made peace with it when he realized Shahid was mistaking Yexing for Yexing. Raman was too high to realize it was Yexing with short hair. Had Yexing not thought Raman was looking for someone else, he would have slept with him. I know Raman committed SA, and that's a deal breaker for me, but I, too, have forgiven Raman. There are bad people who do good things and there are good people who do bad things. Raman is a good person. He messed big time, but he's never tried to deny it. He's emotionally immature but Yexing is willing to teach him, and more importantly, he's willing to learn to be better. I think Raman is great. I love them together.
I get that why you see him that way. If I may humanize him a bit... Raman isn't a drunken rapist. To me, that makes him sound like someone who drinks all day and hides behind alcohol whenever he does something wrong. He had just been shot twice and was high on morphine and opium for the pain. This was not him smoking it as a drug addict, but Dr Caleb giving it to him for pain management. So, as bad as that situation was, it really isn't entirely his fault. He swore off opium and morphine after that so he would never make that mistake again. He also apologized to Yexing that morning and again 4 years later.
As for the sexual harassment of an unwilling Yexing.... Yexing himself admitted in the story that he was giving Raman mixed signals. He never gave Raman a firm no. He allowed Raman to do these things. Yexing was jerking off to his clothes, and prepping himself before bed to sleep with Raman. He even shared his bed with Raman. They slept together whenever Yexing was in town. Yexing hasn't allowed anything of the sort with anyone else. Yexing is not some helpless victim at Raman's mercy. Yexing is baby John Wick. The only reason he ever hesitated is because he thought Raman was only flirting with him because he looked like someone else. If he realized that Raman was looking for him that night but didn't recognize him with short hair, their story would be completely different. Yexing would have consented, they would have gotten together, and people wouldn't hate him. It's not the best start of a relationship, but they genuinely love each other. Raman is a brute, and needs a leash at times, but Yexing wouldn't give him the time of day if he was a bad person.
It's fine if you still dislike him, but I hope you can see there's more to Raman than his one mistake. Look at his relationship Cináed, Dr. Caleb, Mr. Gordon, Devon, or even Albin. Is Raman the best person? No. But he's not a monster either.
My reply was in response to the OP asking "Why is everyone acting like Shahid is so terrible?" to which I gave my personal reasoning. Apologies if I mistakenly replied to you.
Though, I do appreciate your well thought out response, I have to disagree. You say Yesing "never gave Raman a firm no", but in Chapter 38 Yesing is clearly begging him to stop repeatedly, even punching him in the mouth afterwards. A few chapters before that Raman smacked him in the forehead with his dick (gross) which earned him a punch to the nuts. Raman violated Yesing too many times for me to look past. Yesing may want him later in the story but to me that still doesn't excuse Raman's sexually forceful behavior earlier. I dislike men who don't understand when "no" means "no". That's just me though, I understand you may see things differently.
It's so hilarious 'cause as a Cináed x Lou lover and truther I was patiently waiting for Raman and Yexing's past reveal just to see everyone bitch and moan since they wanted the second couple so much lol
Tbh even now I kinda just speed read over Yexing and Raman's scenes 'cause I'm bored of seeing them bone all the time. I don't think Raman is a terrible guy, tho. He's been traumatized and hunted down since he was a child. His family and friends have been murdered just for being close to him. In a time where mental health wasn't taken seriously nor really studied as a medical field ((they literally threw women in cells for going through menopause)) I feel like being loose with your bed partners is the least he could have done to cope.

Why is everyone acting like Shahid is so terrible. In the beginning everyone preferred him over Kinard, but now that him and yesing are together they hate him. He hasn’t even slept with anyone else in the current story we are only told he did and he never cheated on Yesing. ******yes I’m aware he raped yesing when he was too high to recognize him and he hasn’t apologized bc he doesn’t remember and yesing has also chosen to move forward and not bring it up. Does that mean he should be forgiven ?? Not really but damn what can we do******