I hang around a few FOSS communities, and the idealism is even more exhausting there. Most people just want to build and use cool or useful things - the zealotry over the FOS part of FOSS has a tendency to produce toxic communities imo.
if you don't see that then maybe you are not meeting the right people. those who do the work just get along fine. they are not bad-mouthing others for not doing it right.
and people who refuse to work with non-free software, that's their choice, that doesn't make them zealots. and i haven't seen any example of where that would make a community toxic.
that doesn't mean that there is no toxicity, i am sure there is. but not more than what you can find right here on hackernews.
I think the zealotry is being protectionist trying to keep things fun and useful and not tainted by the need to extract a profit