the way Tali treats Legion -- by all accounts an intelligent lifeform that was created by her people -- is far worse than anything Ashley does btw
Bioware's audience tend to hate characters that personally offend them, even when those characters make sense in the context of the game's setting. For example in DA:I, Vivienne is the most hated companion because the audience are offended by her views on the Circle and mages, but imo her views are what make her stand out from the rest of the cast, and she's probably the only realistic companion in the medieval-inspired fantasy world, alongside Blackwall (another unpopular companion).
This is an issue I have with most video games. Their audiences are too stupid to realize that a video game universe can depict racism or homophobia without necessarily endorsing it. Dragon Age's universe is always super sexually progressive because its weirdo, autistic, otherkin fans would scream homophobia if it tried to depict how gays were treated in an actual medieval setting.
Some doubtless are, but those who are not think that
any representation of racism or bigotry is the same as endorsing. Their mindsets are so extreme, that they want all that to be erased from reality - from the past, present and future. There's no way such themes can be studied without making them uncomfortable. I suspect that what they feel is paranoia, fear that representing such issues leads to others blindly mimicking that behaviour, or seeing it as justified no matter how it's presented to the audience. And with some scenarios, the latter example might be unavoidable, IMO.