In the first place, few physicians are true heroes. Few physicians are idolized the way the public looks at people such as Michael Jordan. But, even if we are not heroes or celebrities, physicians are needed, because our knowledge allows us to keep people healthy and to help those who are sick. But being needed is no guarantee of being liked or respected. In fact, it tends to work the other way around.
Physicians are powerful, and sick people are vulnerable.
Few things make vulnerable people angrier than when powerful people abuse their power. The public hears about physicians having rallies in Harrisburg to protest high malpractice costs, and now about physicians unionizing to protect their incomes. But the public does not see many references to physicians going to Harrisburg or Washington to lobby about better care for patients, to work for fuller access, and to do those things that assure patients getting appropriate care, because few physicians are doing those things. It is a valuable and important type of public relations, because it shows that physicians really care and will go to bat for their patients. Unionization of physicians would encourage greater abuse from the public, greater regulation by government and business, and probably the opposite of what most physicians want.