Headline undersells how he did this during the 90’s during the Don’t Ask Don’t Tell era. Was not nearly as socially or politically acceptable then as it is now in the US to do that.
And not just for one person, he was the facility adviser of a gay-straight alliance club
There is no excuse, but there is a reason: Lots of people really like hateful, selfish douchebags.
Spite. They love spite. And they cherish unfounded fears.