Am I the only one?

I didn't like it, I didn't even find it cute.

That's always when the vibe kinda comes to a screeching halt, for me. The "cute" is (probably) fine, Japanese put a premium on cuteness so maybe it's not just a compliment for twinks... but the "You sound like a girl"?? You're really going to compare him to a woman right at that moment? Really?!! It's so stupid yet so common in yaoi.

Right, it's so common that i asked myself if there's more behind it, other than"you look/sound like a girl (which makes it ok for me to have sex with you)".
The cliché is that men are (= have to appear) more stoic while having sex and dont let out their voice much, because it’s considered "unmanly", while it’s ok for women to do so. It’s something i noticed in many sex scenes in BL, ukes moan and semes kind of just tease them.
Perhaps you can read the sentence"you're like a girl" as: "(even if it’s humiliating to act like a girl), you're so overwhelmed by pleasure that you let out your voice and act all submissive, just like women do, and it's cute and i like having the power to mess you up".
So men can’t show that they’re feeling it without being compared to women?
The implication that acting like a (stereotype of a) woman is something embarassing seems to be supported by the fact that many BL are (involuntarily? unconsciously?) at least a bit sexist (reinforcement of gender roles, the "i prefer men cause girls are shallow, weak and no fun and they cry and gossip all the time" the “weak, submissive uke” cliché, and so on. Ofc i'm not saying that all of this is happening in this particular manga).
Also, the fact that Tamenaga-san (uke) explained to Tamotsu-kun (seme) that he feels uncomfortable with his "girly" looks doesn’t make things look better. Not that being compared to women is inherently bad, but it reinforces the bias that "real" men shouldn't be be/act in a certain way, plus Tamenaga-san made it clear he didn't like it, so I think it was unrespectful from Tamotsu-kun.
But then again, saying some dumb shit when you’re having sex can happen to everyone.*coughs*
If you liked the story it's fine, I'm not saying it's bad, I enjoyed it too. I just like to flesh stuff out. (￣∇￣")

I think the "sound like a girl" was totally unnecessary. An also, it doesn't make sense he said that cause pages earlier he was saying "I'm calling u cute and pretty, as a man"