The anti-authority/anti-expert theme in American politics isn't a left or right phenomenon. There's a fundamental breakdown in institutional trust within American society which is present on both sides, and the similar approaches to wellness are a vivid expression of this.
It's been well-earned. How many iterations of the food pyramid? How many times have we been told that X is okay, only to find out some decades later that X is in fact, not good for us? Flame retardants, can liners. Don't wear masks. Do wear masks. Okay, we lied, but it was for a good reason. This is safe for pregnant women. Then it turns out not to be safe for pregnant women, but they keep prescribing it anyway. Now that everyone involved is off the board and/or dead, we can admit it: we knew about global warming decades ago. Nobody got locked up for Tuskegee, the psychopath who tortured David Reimer and his brother was lauded as a visionary, and the inventor of the lobotomy got a Nobel Prize for this daring feat of psychosurgery ... just a year before the Soviet Union banned it on moral grounds. Feed some kids radioactive oatmeal, become the head of the American Association for Cancer Research.
Of course experts aren't respected. They've demanded it.