Don't have much to add, other than I first became aware of this connection when Freenode imploded. I wrote in a short essay that
[the] dominant ideology of new Freenode is free speech, anti-LGBT, and adherence to fringe Unix shibboleths such as anti-systemd, anti-Codes of Conduct, and anti anti-RMS.
(src)
Maybe it's connected to the phenomenon of old counter-cultural activist become massive racists.
Except my feeling is it's mostly people who have grown up with Linux as a settled fact of computing life, not Unix greybeards.