Dear Paul Krugman,
Please stop saying stupid things.
Yea, the Berniebros are pretty ignorant of facts, and I really don't get Sanders's campaign at this point (I think I read a theory on why...something about more delegates meaning having a stronger position for determining the party platform). On the other hand, the "center-left" thought the Iraq war was a good idea. They supported financial deregulation that gave us the financial crisis and lesser depression. More recently they wanted to make a deal with Republicans to cut Social Security and Medicare because grand bargain mysticism rules them. The [professional] center-left is hardly the home of "intellectual values".
Of course there are fact challenged liberals and other left wing types. The more progressive activists of the Democratic party tend to be anti-GMO, and think that organic and local = sustainable. There's also a lot of anti-nuclear [power] that tends to be more left-wing. But, fortunately I think, those types are a (loud) minority within the party. The liberal sphere of our politics is, as a whole pro-science, pro-facts, and pro-intellect. So the saying "facts have a well known liberal bias" is accurate, but the second you try and subdivide the left you leave yourself very open to the failings of whichever branch you have decided is the bearer of The Truth.
The center left has some pretty fucking horrible failings. Way out there left wing nuts may have some kooky aspects, but no one has ever listened to them...even when they have been right.