Because people are obsessed with all this politically correctness and want to put it everywhere. They are changing languages, making a great scientist cry on TV, indoctrinating children in school about all this gender war they are creating.
They are not able to just see that this is a game, and all that matters is fun. They need to project real life problems over it in order to feel morally superior, unbiased beings that condemn whatever they think they should.
They look at a game as a description of society, without looking at the history of it or of the sector.
About Rek'sai, to me it's a "it". As it is malph, gnar, kha, and the rest. I woudn't care if every champ in the game was indian, mexican, chinese or latino, all that matters is that they game is fun.