I think you forgot that the red head was always nice towards him and very clear about his intentions. He literally didn't deserve to be treated and looked at like a nasty insect. You are free to reread the chapters where he appeared and how he behavioued. Drawing a clear line and being nice don't contradict.
"He could be a good colleauge if he didn't say unnecessary stuff" while being the one who spilled the beans and being obviouse about his feelings towards his best friend.
"The longer I think about the more unfair it seems. It's not like I was the one to reveal my preferences first" is an extrem arrogant and selfish and he judges red head for being open about his preferences, just because he is a coward and goody-two-shows himself.
And then he goes and ask questions he himself wouldn't have liked to hear, would even get mad about and forces red head to confess to him.
"Whatever feelings he might have for me are irrelevant" okay? So why does he make a big deal out of it? Why can't he just say "you were right about my friend and I and we are together"?
Why does he force him to open up, when he doesn't want that himself?
"I warned him to stay in his own lane" and "it was a waste of time" Dude was never pushy, never mean, never pryed too much and didn't force himself on MC.
So yes, it feels very much that he disgusted by the thought of another man being interested him, over than his bf and everything about this was an ass-movement
Would yall mind telling me your opinions of the red haired guy? I need to better my understanding at this point cus I might've been too overprotective ( ̄∇ ̄")