The problem is that gay dudes are trying to pick up young (all characters are still in high school) dude in an aggressive fashion.
In addition to this - none of the characters in the "main" persona games (3, 4, and 5 - I don't like it either don't fucking @ me) are gay. None of the relationships are gay and all of the characters are canonically straight (and frequently even have implied pairings, assuming the MC doesn't mess it up). People got really,
really mad about it in Persona 4 because they went full bore with leaving SJW checkboxes unchecked (fat chicks are gross, the coded gay dude isn't gay, the coded trans girl realizes she's going to make a huge mistake).
This "vaguely gay scene at a beach" in Persona 5 was also repeated from Persona 4 and Persona 3 - but these idiots miss that the characters in your party are supposed be immature because they're school kids in shitty situations, not grown adults that are supposed to know better.
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Kanji's whole arc was, essentially, "maybe I'm gay because I like sewing and girls scare me".
Kanji's whole arc ended, essentially "nah that's dumb, I can like to sew and still be into chicks. Part of being a man is being your own man, so I should not be afraid to do "non manly" things like sew and hang out with my mom"