MD doctors (and even to a large extent DO doctors nowadays) are philosophically grounded on science. An MD fundamentally practices science. That used to be one of the key differences between MD and DO physicians, but science has been so successful at advancing the standard of care that DOs cannot ignore it anymore. That's just to say that MDs are expected to be fluent in science and it's not some arbitrary expectation of bureaucracy run amok.
Due to the high trust they get from the public, I have run into many MDs who are used to making unfounded assertions with little pushback.
Why is this? MDs are among the people I trust the least, along with lawyers, financial advisors, and real-estate agents.
Information asymmetry
"fasting is a disaster for the body" says radio MD with complete confidence.. one of my personal favorites
An MD does not practice science.
Science is a process of discovering new knowledge through experiments.
An MD is much more akin to an engineer that applies scientific knowledge (and yes, some proportion of both MDs and engineers do create new knowledge through experiments and thus do science, but it's not the baseline expectation).