I think everyone who knows Glinner has some kind of love-hate relationship with him. He can be lovely, we know that he can be brave and principled, and sometimes he's just a bit of a cunt.
And yes, because he was prepared to be brave and principled on this one thing, he lost his marriage, was blacklisted from the work that he loved, and most of the people he thought were his friends publicly betrayed him. I wouldn't be at all surprised if he were drinking too much. It's what Irish depressives do when they're under stress.
I also feel that he's often his worst enemy, not just in how he expresses himself but also in not picking his fights cleverly. I unfollowed him when he decided that Katie Herzog and Jesse Singal were the biggest enemies of the people - and I could understand why he felt aggrieved at them, but he insisted on going on and on and on about it until he'd proved their point.
He might be in a healthier place if he realised that everyone else has their own shit going on, and nobody is under any obligation to elevate him.
I don't know what his beef is with JKR (who I also don't always agree with!) I assume that, because he's been so heavily ostracised in the entertainment industry, he feels a kinship with the most famous person who's taken a similar stance and he can't understand why she seems to be studiously ignoring him.
I doubt if it's animosity on JKR's part. She picks her fights as carefully as she chooses her words, and she's probably concluded with Glinner that he's a loose cannon who brings an entire side order of his personal drama whenever you engage with him. We've all got our own shit and we don't necessarily have the bandwidth to prioritise Graham's shit.
I used to have a friend who I loved dearly, and gradually drifted away from because she was constantly embroiled in some online drama. As much as I liked her, I didn't feel obliged to have exactly the same list of friends and enemies as she did, and eventually I got tired of being berated for not showing up to defend her when she was attacked in some 900-comment thread below a blogpost I hadn't read. Sometimes life's just too short.