In my experience, the worst people to have in a group project are useful assholes. The people who volunteer a lot of time, but are so miserable to deal with that they are still a net negative when it comes to how many people they scare off or prevent from joining the project because they create such a toxic environment.

I dont know anything about this person or the python politics, maybe he fits in this category, maybe he doesn't. However i strongly feel "donating lots of time" is not an excuse for being an asshole.