-
You do know there's a significant difference between people choosing pronouns for themselves and people applying them to inanimate objects? Maybe you could work slowly from that starting point to the idea that sometimes the person applying that gender (usually not theirs) to the inanimate objects is revealing something less than admirable about their attitude to people of that gender. Although, if you're having trouble distinguishing between inanimate objects and people, that journey may involve a lot of tiny steps.
Imagine getting mad over giving bikes pronouns...and yet people can change their own pronouns freely...this seems like a very childish discussion