MalàStrana said:
Finn is a black dude who deserts his masters

There have been plenty of people of different nationalities throughout history who have defected from whatever faction they held to be true until they saw otherwise.

his main job was toilet cleaner

That was only his job when he was stationed on SKB

who gets a new name thanks to a white man

Oscar is from Guatemala. Also The First Order gave him the name FN-2187 and Poe gave him the name Finn as a way to acknowledge as a fellow human being/sentient.

who drinks the same water as an animal

It’s not like he was forced to by the First Order; he does it because he had a long walk through the desert and pretty much did it for survival.

and who gets beaten by Rey because he’s accused of having stolen the jacket of a white man

Supposed thievery would be bad no matter the nationality.

by a white ginger droïd

Are you serious?