Scott D. Pierce: ‘Mom’ isn’t about mom at all anymore

Not since ABC’s “Cougar Town” has a TV sitcom turned into something that has nothing to do with its title more than CBS’ “Mom.”When “Mom” premiered in 2013, it was about Christy (Anna Faris), a recovering alcoholic and mother of two, whose teenage daughter was pregnant. And Christy’s estranged mother, recovering alcoholic Bonnie (Allison Janney), suddenly re-entered her life.“Mom” was good when it debuted. Very good, even. But wha