Do you think action series with gay male protagonist would survive in Jump?
Any series can survive as long as it's interesting.
Do you think MHA, BC, Kimetsu would have the same popularity if Deku, Asta, Tanjiro would be gay?
What makes you so sure they aren't?
Granted, Deku and Asta have girl crushes (which still doesn't guarantee they are straight, but close enough), but as far as I can remember Tanjiro, Luffy, Senku and Hinata never expressed romantic interest in anyone. You're just making assumptions here.
If Tanjiro suddenly started blushing around Inosuke in the next chapter, do you think people would stop following the series?
Drawbacks are Jump main audience are boys/men and they could not accept gay male protagonist.
You're sounding a little racist/sexist here. Surely not all Japanese men are close-minded bigots.
And roughly half of the readers are women anyway.
How many female protagonist have Jump in action series which are less 'controversial' than gay male.
Including Yui Kamio, three. Four if we count the girl from Mitama as the main character (she has at least three times more screentime than Mitama).
If we can have 20% women, surely there's room for one gay guy.
You really think Japan wants to use China as their moral compass?
Even most 'fujo' stuff don't have canon gay.
So?
It's not like they will stop liking the series when there are actual gay relationships in it. Quite the opposite.
Regardles I could see Jump greenlight gay action series but first they test water with Jump Plus series.
That'd be cool. Though Jump+has been using gay main characters for quite a while already.