The n-word is not a slur “in and of itself” either; people can use it in non-pejorative situations… just as pronouns. The problem is the words being used to rob people of their dignity by invoking their minority status against them.

So yes, in that context, pronouns can be slurs against trans people.

No one is railing against “unintentional misgendering,” which happens to everyone. Though if you aren’t sure, non-gendered pronouns are a perfectly suitable alternative.