I think what you're saying is, black people shouldn't bring up the past because it annoys white people who are best in a position to help them. And you don't want to bite the hand that feeds you.
Not just black people. My example initially was a Puerto Rican friend. But no, that's not my point.
In a society that's a democracy, you need allies in order to achieve your political goals. If you set out seeking to convince people they're guilty of something because they're white, it's a losing battle. Several have said that's not necessarily what white privilege means, but as I've said, operationally, many times that's the approach taken and how it's used in the wild.
So you have an effort by minorities and well meaning progressives to educate people about their white privilege, all the while under the banner of identity politics...where your identity as a minority, or a racial group, or your sexual orientation, or any other category you believe you belong to, is paramount and it's the frame of reference from which the arguments for resolutions are geared. The natural result of this approach will be to turn off white folks who otherwise could be allies to minorities to achieve goals they are interested in, but because this is the chosen approach, they will turn them off.
It's not because white people can't handle the past. But it is because most white folks, and really, folks in general regardless of race, don't want to be blamed, shamed, or guilted for things they never did. And reasonably so.
So when white privilege, white guilt, intersectionality, and identity politics is operationalized and actually used in conversations, I've seen over and over again appeals made to past injustices by people who aren't those they're talking to, being used as a justification for the people they are talking to, to do something that may be counter to their interests presently. This is a losing strategy.
Oddly enough, those very people can be won over to the causes of minorities by a simple change of approach, by a change of framework of the argument. Instead of coming from a position of "I'm the oppressed, white folks owe minorities these fixes to their situations due to past injustices" (I know it doesn't have to be this approach, but more often than not it is) they can come at it from a position of "Being working class, or poor, or lower middle class in America is tough because the deck is stacked against us. We have less options, the rules for us aren't the same as they are for the rich. The judicial system isn't the same for us as it is for the rich. So much in society is unfair for us because we are in this situation, and we should band together and fight for better opportunities for us, better education for our kids, better retraining opportunities, better justice in the courts, better treatment by law enforcement, etc."
On one hand, you have an "us vs them" mentality where it's minorities against whites. On the other hand you have a cross-racial representation of folks numbering in the many millions who can talk to each other with "us" language, and talk about common injustices and pitfalls of being in that category, that check almost all of the same boxes that they were trying to get checked by using their "white privilege" and identity politics approaches.
But it's not as simple as just changing language, it's changing the entire framework of how you relate in society to other people from one where we're disadvantaged by identities we put on like race, to situations we don't necessarily chose like being working class and being continually screwed by a system stacked against us by the rich.