I have no idea by what criteria, precisely, these videos or the PragerU videos were marked restricted. Neither does PragerU, for that matter; Google doesn't surface that level of detail on the Restricted algorithm to end-users. I've been making educated guesses at the detailed cause, but it's somewhat irrelevant; the answer is, really, "Google's algorithm deems this content should be restricted."

By that criteria, MSNBC and PragerU appear to be treated the same way.

(Edit: FWIW, I went ahead and clicked through one video and that micro-sample should probably be flagged for "politics;" pundit accusing the President of, at best, being ignorant of science, and at worst, misleading the American people intentionally. That's clearly inflammatory political content).