You're speaking in absolutes but a lot depends on quality.
Yes, factory meat can be bad for you, but pastured meat is good for you. I know for myself, if I'm feeling worn out, at the end of the day, one mouthful of good quality meat and I am instantly revived.
Yes, pasteurized dairy causes all sorts of problems, but grass fed, organic, unpasteurised dairy can be a good food for some people, especially fermented.
The reason you feel ill after Mac & Cheese could be the processed cheese, for sure, but could also be the wheat.
The reason you feel sick after Thanksgiving is probably not the meat. How much meat would you eat and how much other stuff? Do you think it could be overeating in general?
I don't judge people on what they eat either.
But I'm keen on them being fully informed.