i think there’s a part of buck—a part that exists very, very deep in his subconscious—that has feared being accused of being in love with eddie from the moment he realized he liked men. like, if we circle back to 7x05, eddie is the only person buck is scared of coming out to. he does it fine with everyone else, on accident, brushing off the importance of it. but with eddie we had a whole episode avoiding it. his relationship with eddie is the only one that could be fundamentally impacted by that change. a part of buck was maybe scared, irrationally, that eddie might think it now means he is in love with him.
so when tommy brings it up in 8x11, this thing that has been eating away at buck for almost a year at this point, he goads tommy into saying it. it’s obvious tommy was referring to eddie but buck wanted him to voice it, he wanted someone, anyone to say it aloud. he wanted to hear those fears said to him for the first time, maybe because in a way it almost validates this crazy part of him that he repressed down. honestly, i think buck is relieved someone finally said it so he could start arguing his case.
the problem is, when he finally starts speaking the arguments he’d prepared—“eddie’s straight”, “this isn’t even really his house”, “it just isn’t like that”—he realizes that, actually, no one actually believes him. that’s what pisses him off the most, what sent him over the edge with tommy. then the, “everyone wants me to be hopelessly pining for my straight best friend,” when absolutely no one said that! those are his own fears that have manifested. and what’s even worse than all this is—it might even be true. but i think buck will avoid that until something snaps.