The break point for me is always my suspension of disbelief when it comes to a romance between someone scared for their life on the most basic level and someone who needs to see them and all people like them as something less than human in order to work in and for the oppressive system.

I think a strategy to address that has been to make the enemy on the oppressive side "not needlessly cruel" and maybe make them question the order of things in some ways right from the start. Which... Is not enough for me to actually feel like rooting for the romance.