If scientific methods are thought of as something special and other, separated by context and ritual from everyday life, then when someone like your average journalist looks at scientific results, they're parsed as essentially an argument from authority and get evaluated against the opinions of other, nonscientific authorities
Well unless you understand the arguments underlying the science, they are arguments from authority.
Furthermore the attitude implicit in the BBC policy goes a long way toward making science even more a case of argument from authority.
Think about it, suppose you're a journalist, how do you decide which arguments have "scientific backing"? Do you
a) analyze the arguments yourself to see how valid they sound?
or
b) look at the credentials of the person making that argument?
Note that (b) is a lot easier then (a) to a reporter without much scientific training? Furthermore, even if you do analyze the arguments, you'll have to answer to your superior if you reach a conclusion that differs from (b).
It's not obvious what rule a journalist could use that is quick and easy to apply with no domain specific knowledge, would rule out taking creationism or MMR hysteria seriously, but allow taking cryonics seriously.
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