They wouldn't be realistic without predispositions-
If I was even remotely concerned about "realism", I wouldn't buy fantasy games in the first place.
Does anyone who makes this garbage argument ever step back and actually look at it? It's totally fine for everyone you meet to be a goddamn superhero, capable of powerful magic and impossible feats of physicality, but if they're all "bisexual", that's crossing some invisible line for you?
Tell me, is "playersexuality" the last straw in the slow erosion of your suspension of disbelief over time? Or would your immersion be instantly shattered even if the game was set in the real world and dealt with utterly mundane events?
hopefully your entire life isn't people of every gender clawing at you all the time.
Why? You jelly?