I’m sorry your mom said that about your queerplatonic partner.
Sometimes parents think they are doing what is best for their teen, and they might mean well from their point of view, but they end up overstepping or saying something pretty horrible in the process. I personally don't think a parent should get involved in controlling their teen’s dating life unless they notice that abuse is happening.
Idk if a parent trying to control someone’s dating life has really ever gone that well tbh. My own have tried controlling who I date before and have tried to talk me out of being with certain people before. The only thing that led to was me being very annoyed at my parents and telling them less & hiding more from them.