"They" can also just he normal people who don't want to be wrong. Doctors are famous for their humility and self reflection.
The cholesterol heart hypothesis was pushed by ancel Keys, who has since been shown to be a dishonest academic, leaving out data, or abandoning research if the results didn't math the preconceived conclusions. https://en.m.wikipedia.org/wiki/Ancel_Keys
In medicine, like many fields, sometimes the old guard has to retire out before change can happen.
I'm also a !carnivore@lemm.ee and I've satisfied myself that LDL by itself is not a risk factor I should be concerned with.