While I think a lot of the medical stuff is nutty...
I ignore "your job is to..." comments coming from people whose only purpose at Mudcat seems to be to actively seek out that which pisses them off. It's an Internet thing. Recreational offendedness. It's how people avoid dealing with things they can't deal with - go on line and try to make OTHER people miserable. It's in a bunch of different threads.

Use let him have his reaction, and move on. You don't have to answer him.