The problem is that fundamentally misunderstands what a class is. Whiteness is a socially constructed tool used to protect and uphold the bourgeois in the imperial core and economically dominate those considered non-white, but it isn't a class in and of itself because it does not imply anything about economic production and ownership thereof or labour and its surplus.
Elimination of the bourgeois would eliminate whiteness as a social construct because the bourgeois' economic domination would end and the need to delineate white from non-white would also end, so your instincts here are right, they just needed a little nuancing.