
I can understand where you’re coming from but just imagine fighting for the love you have for a person and telling them eveytime without getting a proper rejection or acception and being left in the dark. A big role why he was so mad is that Keito was straight that’s why Masayuki wasn’t a pushover but when a guy comes to Keith pushy as ever and getting a chance more importantly that the person is a man wouldn’t that make us all frustrated?

He can be sad but there’s still no reason for him to be angry like that. I would understand frustration and sadness and helplessness, but anger like that just comes from a bitter and spiteful place that it shouldn’t. Masayuki never pushed past harmless flirtations that’s Keito never (clearly) took seriously but instead a joke between friends. Not gonna lie, he should have been more direct (cause I wouldn’t have got the hint either).
If your crush chooses someone else over you, you don’t have the right to be mad Masayuki. It’s just the way life is.