That's very interesting. My niece did a paper on subliminal marketing in her MBA program, using "American Idol" as her subject. One of the things in her paper was that, on the show "American Idol", if the producers want to get rid of a contestant, they'll use a lot of red on the big projection screen behind them. Something about that causes the viewer to feel less friendly towards the person.
I don't for a minute think these are just random choices by MSNBCs set designers.
That much red is used to raise the candidates heart rates, increase anxiety and irritability. It's a cheap tactic by MSNC & Politico hoping to make news rather than present a debate of ideas.