It's often hard to know what's a good credential in somebody else's field. Doing this requires knowing how much to trust the PhD from any particular school, how much to trust journals in the field, how much to trust the department hiring process, etc. Remember, frauds and phonies have strong incentives to look respectable, so there's a lot of mimicry in the academy.
One of the major things people typically learn while getting their PhD is who to trust in their particular subfield; this isn't something an outsider can do accurately in two minutes.
I just saw this link on a pop-news site.
It's a PDF file showing how good BBC's reporting of science news is in general, but more specifically it reports about the fact that the journalists give far too much credit to arguments from people who have no scientific backing for their argument.
http://www.bbc.co.uk/bbctrust/assets/files/pdf/our_work/science_impartiality/science_impartiality.pdf