Melissa Harris-Perry may be too progressive for the new MSNBC. The anchor, who has hosted a weekend program on the NBCUniversal-owned cable-news outlet since 2012, said she will not host her show this weekend in what appears to be a significant difference of opinion regarding her role at the network, which has in recent months focused more intently on breaking-news coverage and politics in recent months. “Here is the reality: Our show was taken — without comment or discussion or notice — in the midst of an election season,” Harris-Perry wrote in a note that was reported previously by the New York Times, then...