Responses

I think because you know that the second ML wont end up with MC, your brain makes it uncomfortable for you to find happiness in their fluffy scenes because that's your mind protecting you from getting hurt when they dont end up together. So it's not because you feel that the red flag ML is the best option for the MC, you know he's toxic. But you know how the story will end, therefore the brain is trying to find ways to cope with the inevitable.
I felt so uncomfortable w/ the scene w/ mc and second ML idk why, they just seem too happy and it just feels weird to me HAHAHA my brain has been completely tampered with chat.