This is an excellent bill. I'm in medical school right now, and perhaps I can offer some insight.
Insurance companies are basing doctors compensation on asking patients lifestyle questions and putting these answers in medical records. In some cases (diet, exercise, tobacco, alcohol use) such questions are helpful medically. In others - The "gun" question is one such case - they are not. The reason it even came into play is probably as a result of liberals in management at said insurance companies.
Furthermore, the entire medical establishment has taken a hard turn to the left somewhere along the line. While I'm not sure if this is true of practicing physicians, the AMA, and state medical societies it certainly seems true here in academic medicine.
So though it might seem a bit obscure, such a bill is actually necessary.
You will find that most surgeons are conservative, and almost all of the rest of the mds are liberals.