In a world where remarks can be examined in polite discourse, I’d ask the person who said “Check your privilege” to me to first explain the remark without using the word “white”, “Caucasian”, “honky”, “Westerner”, “slave owner [white]” et al. Then when they could not, I tell them that they were being racist and offensive.
they are offensive by being
the very fact they exist and breathe American air is offensive