Harvard doesn’t give grades. You either pass, fail, or pass with honors, more or less entirely at the whim of your professors.
It’s much more of a social club than a school, and being denied a degree is more akin to having your country club membership revoked than your credentials refuted.
It’s almost pro-forma, as the real benefit of attending Harvard is rubbing shoulders with the children of billionaires. The goal is to find someone willing to become your financial patron, not to hold a piece of paper confirming that you did all your homework.
If these kids are on the outs with the school board, they’ve already been blacklisted by anyone that matters.