Let me refocus that to highlight the silliness:
> If doctors get it wrong in areas you know about then why should one think they get it right in areas you don't know about?
If my doctor knows not even the slightest tiniest thing about computers, the internet, etc., I'm still going to trust him on medicinal matters.
If your doctor wrote articles about computers and got it wrong would you be willing to trust him/her on articles about Syria? Tax policy? Politics? You would trust your doctor in the area of his/her expertise and not necessarily about other areas.
Some are. Some aren't. But if you're not an expert in the same area, how can you judge?
(eg. "MD" in Private Eye is a doctor and therefore reasonably qualified to report on medical things.)