What was the thing with the Irish Republican Army...
Oregon Mass Shooter Lived in SoCal, Sympathized With Irish Republican Army
Guy got his programming wrong - it was suppose to be the NRA...
Especially odd since the IRA has been out of the public eye for some time now.
I speculate it grew out of hatred for his British father and background. Getting off on British troops (i.e. his father by proxy) being wounded and killed by the IRA.