You made an argument that because someone went to medical school that they're more trustworthy...and again broad strokes, sure. You are relying on their credentials though. You cannot possibly conduct a thorough enough background check to know if they are skilled enough to conduct your surgery.

While this is generally more reliable than say...taking their word for it, it also is possible for credentialed people to slip through the cracks:

https://en.wikipedia.org/wiki/Christopher_Duntsch

I have nothing against universities, but the largely for-profit educational system in America is not the only way formal education can ever possibly work. There are universities in other countries that don't rely on cronyism, nepotism, discrimination, and wealth to qualify who gets into the programs.