Often the problem is that the guy who has made something his career posts incorrect things more often than the guy who hasn't. Some of the reasons for these are:

- self-interest

  - intentionally since it protects their interests

  - accidental since they've spent so much time they need it to be meaningful

  - accidental since they want to please their fellow experts

  - intentionally since they want to go with the herd

- selection bias towards being someone who cares about this very much goes with lack of aptitude

- historical bias

  - most people are better equipped than experts to spot paradigm shifts because experts are over-indexed on the status quo

- no field expertise

Ultimately, it's up to you how you weight people's opinion, and may each person's epistemology serve them appropriately.