Yes, Virginia, MSNBC is liberal, and they supported Hillary (or at least were/are vehemently against Trump), and everyone expected Hillary was going to be president two years ago, so naturally MSNBC would not have dreamed of conducting such a hostile interview with Bill at that time.
And yes, the Clintons have no more political clout, either as high office holders or as party leaders, given the way the Democratic party has shifted. The aim of the Left in the Me Too movement is not so much to dredge up Bill's old sex scandals as it is to hit Trump for his, in order to hurt him politically.