Not that absent fathers are not a problem, they are. Perhaps one of the biggest problems in this country.
But in mass shooters what you find is that they are always liberals.
A conservative knows they are responsible for themselves and have a balanced attitude toward the world. It is not unjust but it is indifferent. Bad things will just happen. It is not a case of someone has it in for you because you stubbed your toe, your homework fell out of your backpack, you planned to do something and it rains. You are not the whipping boy of the universe but you are not the favorite child either. You will have good and bad fortune.
There are times when those bad things will be caused by other humans. Small slights, unjust accusations, losing because the other guy cheated, it is all part of life. And it hurts. But everyone goes through that. The world is unfair, accept it and move on. Try to improve where you can.
The liberal thinks that the world is naturally fair, just and wonderful. If things go wrong it is because someone else made it bad. And that someone else must be punished. It is extreme narcissism. The world revolves around them.
Wars have always left a lot of fatherless children.