You are so right but i think actually what uke was doing is not right too. Uke took his jacket and masturbated with it even he doesnt think seme is in love with him and i think nobody will be happy if a random person masturbates with their jacket but seme was much more worse than uke so you are right anyways :33
(also sorry for my bad eng)
It's probably not an easy thing to ask, especially since it's a guy x guy thing. With things in Japan where gay marriage still unrecognized until 2018 and this manga is released in 2015 maybe the author use that as consideration in the seme line if thoughts, thinking about how it would affect him and how others will perceive him if he's found out to be gay/bi. With pushing uke down the seme in a way playing it safe, the seme can still make excuse that he was drunk (even without saying anything the uke already assumed he's drunk) or pretend that he forgot the next day, but if he asked the uke directly and if by any chance the uke doesn't have the same feeling and uke jerking off to his jacket is only a misunderstanding, it's too late, everything is already revealed that he's gay/bi for his friend. And with seme doesn't know how uke would react to that information he's afraid that it could really ruined their relationship. But I'm only talking about Hara and Suga case, it doesn't include other seme with pushing behavior.
Because Japan in general is still homophobic, and going to nii-choume (gay district) is still considered taboo, so it's really hard to talk heart to heart about your romantic feelings towards other men that you're still not sure has the same feeling as you. In this story case or other story with similar backround (unlike where seme is a brutal sex maniac) harrassing the uke is safer than admiting you like him. Because you can still make excuse that it was just a joke or you're drunk or other excuses. While if you confess and it didn't go well, you could be shunned by your friend, family, or society.

WHY DO SEMES THINK SEXUALLY HARASSING THEIR CRUSH IS BETTER THAN JUST CONFESSING? What the actual fuck, another great manga ruined for me for the same reason.