Cultural Marxism constantly expands by inventing new victim groups to alienate from the core population. Among the most recent is those who base their personal identity on being overweight, and are oppressed by those who wield “thin privilege” by being in better shape.

But what about people who had a weight problem, but through self-discipline got the better of it? Are they to be hated for being oppressors too?

Yes. In a piece from last year, Everyday Feminism explains why (bold in original):

Furthermore, if you think you deserve anything because you worked for it, you are doubly bad:

That would make you not only privileged but an unclean thought criminal.

Whatever burden you may bear, struggling to overcome it is counterproductive, because success would only turn you into an oppressor with privilege. Egalitarianism decrees that everyone is equal, whether they wallow in self-indulgence or struggle to improve themselves. However, those with privilege are less equal, because they oppress sacred victims. The only justifiable behavior is to whine, snivel, and throw tantrums — which liberals do relentlessly, thus securing the moral high ground.