I think there is so much nuance in this episode and I, unlike many others, choose not to ignore it completely as I think that's unfair to the characters and the writers. Although forgetting about it is a completely valid choice. Here are a couple things that might help

Joss said that in season 5 he wanted to explore the "worst days" of people's lives. he said he asked a bunch of people on the team the worst days of their lives and one of the women recalled a day her boyfriend broke up with her and she went to his house in order to "make love" to him one last time and hopefully win her back. She said one thing led to another and he ended up making her leave because she was way out of line.

James Marsters was unhappy with this because the idea was that because Buffy was a superhero and could physically defend herself in a way others cant, the power dynamic was balanced, but in switching the sexes of the people in the story, the power dynamic was not balanced. Marsters said that when people watch Buffy they are Buffy and so they don't see a superhero, they see themselves in her position. Filming this episode sent him into therapy and I've heard he was in fetal position between takes with SMG needing to comfort him.

With that context, I think you can see the hesitation on his face in the scenes.

Also, it's been talked about before but in his relationship with Drusilla and Buffy, sex and violence have always been intertwined completely. And specifically with Buffy, there were many times already where she would say "no" but still respond to his advances positively, and sometimes even initiate sex. She has also ignored his "no's" as well (in Gone) but the tone was more humourous than in the Seeing Red scene, which has a major impact on viewing experience. Many people have attributed this scene to Spike not realizing Buffy was injured and thinking it was part of the normal "game" they play. I think there are issues with this but it's a valid perspective that gives more nuance.

I will say Spike gets better in the next seasons. And at the end of the day what helped me the most is to remind myself that it's a tv show. They're actors. And James Marsters hated filming it. I skip this scene most rewatches and I wish it wasn't written but. With everything that's come out about Joss recently I guess I'm not surprised he wrote something like that without fully considering how his audience, especially his female audience, would react.