This of course in no way justifies his actions. And while I think that the individual in the end is responsible for their actions, I think this really puts a lot of the blood on the muslim community.
The father had earlier said that "homosexuals will be punished by god". This makes it pretty clear that he has some rampant homophobia inside him that has trickled down to his son. If you're a straight man, worst case scenario you might beat up a gay guy, but if you're gay you're going to end up wit a self-loathing man who has an identity in chaos.
The muslim community MUST actively weed out all forms of homophobia. I am myself brought up in a muslim family, but I'm just blessed to have parents who are both muslim and accepting of who I am. The reason I feel conflicted about this now is because hadn't my father been the gentle spirit he is, had I ended up with another more strict muslim father, maybe I would too been omar.
But the muslim community as a whole still listens so much to the Arabic world so much. We have an issue in Sweden of a muslim man in politics refusing to shake hands with women, and he was immediately relieved of his duties. There was huge cry-out in media by him and his friends how muslims were oppressed by western norms. In one discussion, one man who himself was ex-muslim, said that they only wanted to break norms if it benefitted their cause; and if they truly wanted to fight norms in society, perhaps they would march with him in the pride parade? None of them responded clearly, they started mumbling, talking about structures in society, believing in what you want to believe in etc. This is where they need to start: it's a clear-cut case, "yes, I'll happily walk in the pride parade. We're all born differently". That's it. I don't want to pander too much to people who hate islam, because I don't agree with them either (all abrahamic religions are equally shit imo).
I know there have been some muslim leaders who have spoken out against homophobia and I applaud that, I just want and need there to be more. I get that you have religious freedom and etc, but women's rights, gay rights and trans rights should be a non-issue. If I could choose, I would demand that all religious foundations must have a program where they take up these issues, otherwise their state-funding should be cut and shouldn't be allowed to have any space in public. It should be that simple. It's not oppressing religion, it's simply forcing religion to adapt to the modern society or die with the 19th century.