The Met’s presentation of “America Today” might even convince a few anti-Bentonites to look anew at this cantankerous and controversial figure, who in his W.P.A. days, was a mentor to Pollock but was later shunned by Abstract Expressionist painters, who considered him hopelessly retrograde and insufficiently cosmopolitan. Or maybe it was Benton who shunned them, abandoning the East Coast for Kansas City, Mo. — he called New York “a highly provincial place” — and adopting a strident anti-intellectualism.