Although it feels a little shoehorned in, and riot could have made a much more fleshed out and interesting Gay champion, that part is not really the issue.
The issue is that they took the relatively fleshed out and interesting story of Varus's old lore, which involved Varus being torn between his duty as a soldier and his true desire to abandon his post in order to protect his family during the noxian invasion, with it ending in tragedy and Varus giving up his humanity in exchange for the means to avenge his family, and changed it to a new story that is essentially Kayn with a plus one, only this Kayn and his plus one are gay. Wait, are we sure this isn't just literally exactly Kayn, but plus one?
The issue is not that Riot are trying to make Varus gay, although a new champion would be a much more respectful and interesting outlet for that anyway in my opinion, Hell, isn't Kayn Gay or Bi according to a few rioters? They could just make it official. The issue is that one of the few pieces of lore that captured this certain Family vs. Duty side of the classic revenge story, and was somewhat relatable and unique, (Plus it had a bit of a punisher vibe, which i am i sucker for the punisher and always have been) was tossed aside for two and a half men with the half being Rhaast #2 with a side of diversity. The new story is completely dis-interesting in my opinion.