There's the crux of it. It's open source, and the developers usually doing the most work seem to be the ones that are less socially... adjusted, while the 'community managers' and people broadly more interested in DEI are carrying less.
Seen it time and time again. I don't have answer to the situation in general.
"Code of Conduct" of course only exists when people have an interest in working together - which GNUesque projects seem to be more focused on.
Relatedly I observe opposite behaviour the plan9 related community generally - where everyone basically maintains their own patch trees. If you don't want to deal with other people or your changes aren't getting upstreamed for some political reason - it's not a big deal. You can just mail your patches to some friends and they'll use it.
In some ways Code of Conducts is another way of enforcing 'business' culture onto programming and hacking.
At the same time, these 'hackers' and major contributors should stick to their own medicine. If they're all focused on the code, then stick to the code. There's no reason to say something offensive, if your goal is to get a better quality code out there. If you think someone is a @$#%(@% or a piece of @$#%#@ or whatever cartoonishly evil phrase you want to use, who cares? just focus on the code.