This indeed is a big deal. People have been told for decades that saturated fat clogs up arteries ( based on questionable studies while ignoring counter evidence). Another example how the vast majority of the 'research' community followed the herd without questionioning. There was some opposition but they were the minority, so they were easy to dismiss/marginalize.
As terrible as the next four years may be for US policymaking, we can hope that weakening Big Food, and undoing vegan religious propaganda, will be areas of progress.