Kylo's arc eclipses Rey's, huh. I find it interesting that people think she should stay a virginal murder-machine, that is better, more pure? Also, does a woman lose her agency in a romantic relationship? Very strange. I think some of it is immaturity, which Star Wars has plenty of; even though Rogue One, shows there is a market for a more mature audience.
It is just because it is an American movie made for an American audience.