First of I like your prespective, it's new.
ok...I think since Eunho is smart and handsome and makes friends with others easily and is generally a seme, the hyung naturally assumed that he is str8 with only an affection towards himself...or maybe the hyung can't accept Eunho love because E kpt confessing his love to him since they were kids even when E didn't know what love between two men really means.
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And last but not least we shouldn't forget the fact that the hyung actually tried to be straight for a while and kinda forced himself into same sex marriage and maybe he thinks that E still has a chance on having girlfriends and living like most people.
i completely understand your second point about the youthful timing of Eunho's very first confession! i'm just hoping Hyung will come to the realization that he shouldn't assume he is straight esp. because H was in a same sex relationship before and after his marriage.
okay, i can understand if Hyung generally isn't interested in Eunho. i just dont like that he is always trying to steer Eunho into being heterosexual. granted we dont know Eunho's sexual preference, what if he likes men generally?
i kinda hope this steers a different route and Eunho can tap into his sexuality and other love interests