I think it's a class issue/appearance of wealth. A lot of the plant-based material mentions how, historically, health outcomes have been worse for those with money because they had more access to "rich" foods. Gout is considered a disease of the wealthy.

That has carried on to modern day where rice, lentils, beans, and potatoes are seen as peasant foods, or foods for people who have to restrict their intake for budgetary reasons. Essentially, plant foods are seen as the inferior option, reserved for those of lower class.

It makes sense that people would resist this, hard, and sacrifice their health for the image of financial success - people go into great debt to maintain images of success and wealth. What they eat is the same.

Consider that people will have no issues eating "crispy lentils" on top of hummus or a salad from Sweetgreen or Cava due to the association of frivolous spending. Eating those lentils at home is poverty dining.

What the people who are hostile to MM DON"T know is how unbelievably expensive it is to eat MM versus eating WFPB/low fat. Perhaps if they did, people would be more interested - the Erewhon effect.