Despite intense backlash to Sen. J.D. Vance’s criticism of “childless cat ladies,” an MSNBC host noted Tuesday that now that yet another Republican waded into the childless attacks, the GOP has shown these are more than just political attacks. Ahead of Donald Trump’s town hall in Flint, Michigan, on Tuesday, Gov. Sarah Huckabee Sanders (R-AR) told rally-goers, “My kids keep me humble,” as she teed up an attack on Vice President Kamala Harris. “Unfortunately, Kamala Harris doesn’t have anything keeping her humble,” said Sanders, an apparent jab that Harris does not have biological children. Wan…