Just reposting this more coherently: It's a visceral reaction when he's already feeling confused from the day before. Sometimes those thoughts aren't very kind, generous, or sympathetic. Sometimes they're selfish and hypocritical, and we hate ourselves for having them. It happens. Moreover, Souta has had very rigid ideas of gender norms, which has been a consistent theme in the story. He even had a hard time processing that he was getting groped because "he's a guy though." And now someone more "fitting" for the role of the heroine comes in, goes through exactly what he went through, and does exactly what he wanted to do and he's feeling displaced. He can't even tell anyone about what happened to him, not just because of what the ML said, but also as shown in ch2 and ch5 when he's with friends, as a guy, he finds it hard to tell people he was assaulted. It doesn't "make sense" that it happened to him, he's not some pretty girl, etc. It's not the most reasonable feeling, no, and he realises that.
Just reposting this more coherently:
It's a visceral reaction when he's already feeling confused from the day before. Sometimes those thoughts aren't very kind, generous, or sympathetic. Sometimes they're selfish and hypocritical, and we hate ourselves for having them. It happens.
Moreover, Souta has had very rigid ideas of gender norms, which has been a consistent theme in the story. He even had a hard time processing that he was getting groped because "he's a guy though." And now someone more "fitting" for the role of the heroine comes in, goes through exactly what he went through, and does exactly what he wanted to do and he's feeling displaced. He can't even tell anyone about what happened to him, not just because of what the ML said, but also as shown in ch2 and ch5 when he's with friends, as a guy, he finds it hard to tell people he was assaulted. It doesn't "make sense" that it happened to him, he's not some pretty girl, etc. It's not the most reasonable feeling, no, and he realises that.