Here's the problem:

AMA membership accounts for less than 25% of physicians in 2016. They hardly speak for the entire medical profession. They are just another strong lobbying group exerting their influence on legislators. They're in the minority - sorry. Oh yeah - ROFLMAO - I almost forgot. 

https://www.statnews.com/2016/12/22/american-medical-association-divisions/

  http://www.theblaze.com/contributions/why-the-ama-endorses-obamacare-but-your-doctor-does-not/