He was an 18 year old boy dating a 33 year old woman. From that alone you know he has mom issues. Most likely his mother is a controlling, confining... claustrophobic power in his life. So powerful in shaping his identity that he seeks her out again and again in his relationships.
OK Freud...I thought you were an engineer? You cannot know any of what you wrote-it is guessing. He is an adult at 18, old enough to vote and to enlist in the military, and we do not know what sort of relationship he and the woman had, or how long they even knew each other.
There are some people who are just disgusted by gay sex. It could be a simple combination of disgust and and someone who is really violent and angry.
He also is a NeoNazi, they have a long history of violence and hate. Again, that seems more likely than Freudian theories.
Those people who died were men, and I feel very sad for them (I would have either way). I can even try to have empathy for this man, but it won't help. Sometimes people just turn to hate movements, and when they are that far gone there is not much anyone can do. I certainly do not want the MRM tainted by neonazi propaganda at all, so I do not think our movement reaching out to that particular group is a good idea. Hate breeds hate, and they will simply bring it here.