You are actually arguing that it was right.
> The guy (Hocko) kept making mistake after mistake and Kent struggled to get him to do anything remotely net positive
That’s not really an excuse for abuse. This kind of comment is why we need a CoC committee in the first place. There is something deeply wrong when community members openly state that insulting other people is ok because they are not productive.
> You can't just fire them, so I understand the frustration here.
You can and should just ignore them. It is not mandatory to engage with people you disagree with and find unproductive especially on the internet where filtering them out is not that difficult.
Less extreme but also working is to just engage them less often. If you slow down the conversation, there is less space for them to annoy you.