Because answers have references, therefore you can (ideally) judge for yourself how good the evidence is.
I think you might as well assume that the people who answer questions do have their own ideologies: for example people have their own favourite sources of information, which might bias the information which they reference in their answers.
Looking at what's currently the most recent answer on the site, for example, the person who answered that seems to show a bias towards official documentation (because they cited a presidential commission report hosted on the NASA web site).
See also this answer to How do we know that our references are reliable?
There's no such thing as a 100% reliable source - Skeptics.SE cannot hope to only present correct answers, but we can aim at minimum level of accuracy which is much, much higher than the typical sources on the web and newspapers.
So, the following guidelines are merely heuristics - every single one is fallible.
(gives a list of guidelines)
See also this answer which tries to sort references or sources of information, in order from less to more reliable.
Such 'bias' about what we consider to be good sources of evidence may appear in answers, for good or for ill.
For example, I remember that in one question like Are GMO crops to blame for farmer suicides in India?, one of the people who answered it thought, to themselves, "Monsanto's web site have a good collection of references to scientific papers/studies which debunk various anti-GMO publications", and they therefore went to Monsanto's web site to look for a suitable reference for their answer.
Looking at their answer, you couldn't have known that the reference was in some way pre-selected by Monsanto.