Zelda guy is clearly cross-dressing to get into Gerudo town. That's how the scene reads on its face, and that's why the 'beard' reveal is okay, imo, if not particularly funny.
It's an entire town of people to trade with but you need to be a woman to enter. The fact that someone would do so isn't outrageous. The portrayal of the Gerudo themselves is awesome, too, so... I don't see much of a problem with it.
Had the male in woman's clothing been somewhere else rather than attempting to get into an all women's town, then I'd see the argument. As it is it's reaching.
Haven't played ME:A or seen any trans character in Horizon so far.