I never saw that before, but it's consistent with his past words and behavior.
Since duncan asked for citations:
Here's ESR having a tantrum and throwing down the gauntlet during Russ Nelson's "Blacks are lazy" scandal that embarassed OSI and rocked the open source community: he insisted OSI get into a mud-fight against political correctness, and he called people in the open source community who disagreed with Russ's "Blacks are lazy" blog posting "fools and thugs":
https://en.wikipedia.org/wiki/Talk:Russ_Nelson#Blacks_are_la...
Note that although Russell withdrew the article, and admitted it was badly written, Eric S. Raymond is on the record as having defended it by accusing people asking Russell to step down as being "fools and thugs". Note that "thug" has been called a "dog whistle" term for "n*gger".
https://aattp.org/thug-just-a-dog-whistle-for-n-word-says-nf...
http://www.eweek.com/c/a/Linux-and-Open-Source/New-OSI-Presi...
Eric S. Raymond wrote: “The people who knew Russ as a Quaker, a pacifist and a gentleman, and no racist, but nevertheless pressured OSI to do the responsible thing and fire him in order to avoid political damage should be equally ashamed,” Raymond said. “Abetting somebody elses witch hunt is no less disgusting than starting your own.”
“Personally, I wanted to fight this on principle,” Raymond said. “Russ resigned the presidency rather than get OSI into that fight, and the board quite properly respected his wishes in the matter. That sacrifice makes me angrier at the fools and thugs who pulled him down.”
http://slashdot.org/~tomhudson/journal/98015