Did you even read everything that authorities learned about the guy? He was an evangelical Christian who went off the rails.
CHARLESTON, S.C. — The man she had married professed to be deeply religious. But after more than seven years with Robert L. Dear Jr., Barbara Micheau had come to see life with him as a kind of hell on earth.
By January 1993, she had had enough. In a sworn affidavit as part of her divorce case, Ms. Micheau described Mr. Dear as a serial philanderer and a problem gambler, a man who kicked her, beat her head against the floor and fathered two children with other women while they were together. He found excuses for his transgressions, she said, in his idiosyncratic views on Christian eschatology and the nature of salvation.
“He claims to be a Christian and is extremely evangelistic, but does not follow the Bible in his actions,” Ms. Micheau said in the court document. “He says that as long as he believes he will be saved, he can do whatever he pleases. He is obsessed with the world coming to an end.”
http://www.nytimes.com/2015/12/02/us/robert-dear-planned-parenthood-shooting.html