I think it's a knee-jerk reaction to the persecution of white people that happens every day.
Whites aren't allowed to be proud of their race or nationality -- only everyone else. Whites are constantly told how awful they are, how they killed Indians, ruined the earth, exploit other peoples, etc.
Whites are having pretty much ALL of the Four Identities taken away from them: Race, Nationality, Religion, and Gender. You might add "Family" to that list as well, as families aren't very cohesive anymore.
Being (novus ordo) Catholic doesn't mean anything, gender roles are being blurred, you can't be proud of your race if you're white, and with the melting pot, people don't identify with any particular culture.