I don’t like to call a spade a spade. I’m more of a “what you’re saying is colonialist”. Attack their point, not the person.
A lot of it goes towards lack of education. Calling someone a racist is insulting to the person, especially if the person is uneducated of their actions. However, if you tell the person what they said is racist because of xyz reasons, they’re more likely to respond positively and stop doing it.
Of course, there will always be those that disagree.