What do you think caused him to kill?
What causes other murderers to want to kill?
I think you are getting at “oh, it must have been the gayness.”
How about the enticement of the same devil that beckons fallen humanity (of which you are a member too, as also am I) into evil hateful things?
An arsonist could set a fire in the kitchen and a fire in the basement and the one would not need to be the cause of the other.
There are many motives for murder. I just thought that since you apparently know what didn’t cause these particular murders then you might know what did.