I don't know. I believe the average internet user has less to gain to feed me wrong info. It happens of course, that is why you shouldn't believe everything you read on the internet.

A fact checker however has economic incentive towards their employers. You can paint them as independent, but the will always be in a precarious situation or are influenced by third party financiers. This does not at all evoke more trust than a random internet person. Trusted source is pretty subjective, but for me "official" fact checkers don't have too much of that.