This is something every pan-racial (for lack of a better term) movement will run into. Every movement needs its foundational myths (in the folkloric sense, not the "stories that are false" sense) and common beliefs to function. When you're trying to unite disparate peoples whose main reason for joining together is to increase political/bargaining power, you're going to have to either choose to prioritize certain narratives over others or create new narratives whole cloth.
The crackers have to label this as a "pan-racial" thing because they don't want to admit that "whiteness" is a construct and they have no culture.
As Chris Hannah once sung, "Just what exactly are the great historical accomplishments of your race that make you proud to be white? Capitalism? Slavery? Genocide? Sit-coms? This is your fucking white-history, my friend. So why don't we start making a history worth being proud of and start fighting the real fucking enemy?".