He was filled with revulsion when he talked to the woman in the church before he started his murderous rampage. He could not withold his contempt for the ideas that some people oppose abortion and homosexuality.
Do you not recall his mention of having to "meet his homosexual boyfriend getting an abortion on a military base?" (Or words to that effect.)
The sort of revulsion he felt after murdering all those people was more along the lines of "Ooooppps! Fumble fingers me." As opposed to Oh My God!! I can't believe I murdered those poor people in cold blood! How can I live with myself after doing such a horrible thing?"
Very little remorse, not nearly so much as if he were horrified at what he had done. He acted more like he had committed a social faux pas than a series of vicious murders.
He was being blocked from leaving the building, he said what he said in order to facillitate his departure. He had no desire to kill these people, at least in the movie I saw. ymmv