Isn't there is a big jump from being proud of "what you are" to being negative about what other people are?
Can people celebrate their White Pride, Black Pride, Irish Pride, Italian Pride, Hutu Pride, Tutsi Pride, Bengali pride, Muslim Pride, Hindu Pride, Catholic Pride, Protestant Pride, Atheist Pride, educated people pride, uneducated people pride, worker pride, filthy rich person pride without putting down the others? Or does pride require that the others must be inferior? What is there to be proud of if the others are just as good?
The Racism of whites against blacks during and after slavery was useful racism because it enabled the whites to exploit the blacks without feeling guilty about exploiting the blacks. After slavery ended the racism enabled the children of the slave owners to not feel guilty about what there parents did.
The English racism or ethnicism against the Irish enabled the English to not feel guilty about being unjust to the Irish. Protestant superiority to Catholicism could work just as well. When the Puritans game to New England their early Justifications for why it was OK to displace the native Americans were based on religious superiority to the Native Americans and were not based so much on racial or ethnic superiority. Once black slaves started being used the justifications for displacing the native Americans became less religious and more racial.
Pol Pot's genocide was class and cultural based. I don't think there is much difference between how class and race and ethnicity and religion are used to justify beliefs about superiority and inferiority and when it is OK for one group to treat members of another group in ways that would be disapproved of if done to a member of your own group.
There is a difference between the attempts at pride that an oppressed minority make to try and heal their battered self esteem and the displays of pride that the privileged groups make to brainwash themselves into not feeling guilty when they use weaker people.
But when white trash abused blacks this was one group trying to heal it's shattered self esteem by doing cruel things to another abused group in order to feel convince themselves of their superiority to somebody and thereby heal themselves.
Some Black comedians noted how happy they were for Arab Muslims to replace Blacks as the hated and feared people in America after 9-11. Blacks got to feel more included in America when whites were willing to include Blacks in their American coalition of Americans hating fearing Arab Muslims.
Is anybody telling Christians or Atheists not to be proud? To Christians and atheists resent it when they are rebuked for proclaiming their superiority? Is there a difference between being proud of what you are and proclaiming superiority? Is it possible to proclaim superiority without indirectly calling others inferior?
Is anybody really telling whites not to be proud? Or are whites just sick of being told not to be racists?