[thaumasiotes]

"Do cigarettes cause cancer?" is both a single issue, and one with no middle ground you could occupy if you wanted to.

"Left vs Right" is not a single issue; claiming "Left is always correct" immediately commits you to one end of a very large number of dimensions.

And what bothers me about the idea "university-affiliated people are more credible; think-tank affiliated people are less credible" is that if you follow it, you will conclude that the left is correct, and the right is wrong... and it's not necessary to look at what the issue is, or what positions each side has taken, before coming to that conclusion.