Once one goes beyond the level of, say, The National Enquirer, the issue is not whether the source is reliable for any particular fact so much as whether the source is overweighting material that tends to attract more mass market interest.  Wikipedia was not created in order to just attract eyeballs.  The problem with, say, The Fox Nation, and The Huffington Post, in other words, is not that they lean right or left, respectively, but that they have a populist lean such that some discretion is in order.  For whatever reason, there is a lot more editor interest in adding (often without context), say, what O'Donnell said about mice with human brains on TV than there is interest in adding what a more "boring" politician like Mitch Daniels said to The Economist.  And there is undoubtedly more reader interest in O'Donnell than in Daniels as well.  But our obligation here is to be encyclopedic.  The Encyclopedia Britannica is often found in academic libraries where it is read by stuffy people who are more interested in an informative read than an entertaining one.   Beyond this, one has to ask how many quotes of this sort even Fox News or HuffPo would have if they were to have a single story on O'Donnell, which is what we are constructing here.  All this to say that an edit that introduced this quote would be considerably more likely to have a consensus supporting its inclusion if it replaced some other controversial, widely criticized or ridiculed remark by the article subject as opposed to adding to them.