Well, you're a ethnomasochist; which is a strange attribute of WEIRD people. No other population group behaves this way. (The Chinese don't bemoan their "privilege" in China; ditto the Nigerians in Nigeria.) But when you tell someone that what they have is ill-gotten, that they are part of a conscious or unconscious scheme which mistreats others, you are dehumanizing them. You are devaluing them. Their efforts are somehow less than the efforts of others solely due to their membership in the group. This is bigotry and to apply it to a whole population group is racism. It's essentially the same as the Antisemitism in Europe leading up to the second world war. Ya know, those Rothschilds controlled everything and their success due to mistreating the native European population.
Shut your mouth, I am Scottish and proud of it. I just don't have to beat and oppress others to feel that way. And you're also wrong when you claim that we are the only moral people ever to have or critique privilege. There are plenty of Chinese activists, for instance, who see the way their government treats the indigenous peoples of their Northern and Southern frontiers to be wrong, despite such protest being deeply illegal and fervently suppressed.
I can't follow your logic at all as far as one's efforts being worth less than others. The whole idea of privilege is that quite the opposite is generally true. We fight to level this relationship, not reverse it.
Sounds like he hit too close to home.
Telling him to shut up doesn't address the point that you know you have no rebuttal for.
There is a big difference between saying group <x> is mistreated and saying that all members of group <y> bear responsibility for the mistreatment of <x>.