I thought that it was odd that he dislikes "user" because it is impersonal (he wouldn't call his mom one), but then he chose replacements that are nearly as impersonal (I'm sure he wouldn't call his mom a buyer or a seller either). "Customer" is going to get very confusing if they start using it for people who aren't actually paying for anything. So while I see his point, I don't think he's improved the situation.