There is nothing wrong with anyone in any church encouraging political involvement. What can't be done legally, by tax law, is to encourage voting for or against any candidate or party. In the article she is clever enough, perhaps with the aid of coaching, to not make blatant statements to vote Democratic and/or for that jerk in the White House now. The message obviously gets through quite easily in this case. But... that's politics.
I used boards and letters to encourage churches 4 years ago to start a Rifleman analogy-- remembering Lucas McCain, The Rifleman, on television, the hero who so often came right in time to save the day. None picked up on the idea that I know of. But that's an example where we have the IRS hog-tied and nothing would come of it, and it's less blatant than Michelle Obama appearing in a church or convention encouraging voting. In either example, theres no guesswork as who the message is meant to support, but there would be no smooth stones needed for the Goliath IRS.