I never got the impression of hatred from him.

would debate anybody who disagreed with him

I mean, debate is the way to test arguments and refine understanding. If your understanding diverges from someone else's (like mine does from yours here), is it wrong to point out why you think they're wrong and either help them understand some part better or be taught by them instead?

I think that's just a different mode of communication and using social media. I know he's chronically ill and believe he describes himself as "cripple", suggesting that his body has forsaken him, which makes IRL social activities difficult and painful.

The beauty of the internet is that you can interact with people there, even if your body can't handle going to the pub or whatever. So I don't blame him for leaning more on his mind than his body and being chronically online if the offline world is chronically hell.

Sad to see yet another active community member get consumed by hatred and frustration

I think the frustration is mostly at the fact that rimu is pursuing a policy other admins have advised against and it's killing his fun. He has stated several times that he doesn't think rimu is totally off-kilter and that he gets the motive, just doesn't agree that it would have any beneficial effect on the fediverse.

That doesn't sound like hatred to me, more the disappointment of seeing a working partner you otherwise respect take steps that make it hard for you to keep working with them.