A change of gender here....

if THIS were their gender and not girls.... what do you think will happen?

It wouldn't be Yandere. It would be just a killing fight between two guys

It would be School Gays and I probabbly wont watch it to find out what will happen, but I guess Makoto Itou will not be hated that much today and that specific famous Yandere icon would vanish.

Trap Fapping is gay

A slightly different story and outlook for the side of Makoto if THAT were to happen. Probably could end in a bloody way, but probably also end like or similar to the ending of most animes featuring two or more guys and one girl, like Ouran HS Host Club and Hana Yori Dango.