"I suppose it was just an insider joke, just being trendy and cool,
when Patrick Volkerding chose the "Dr. Bob" face and the term
"Slack" early in his project."

"Dr. Bob" = Alcoholics Anonymous founder & patron saint

J.R. "Bob" Dobbs = Spawn of Nyarlhotep & OUR patron saint

I hear this ALL THE TIME. "So that's a picture of Dr. Bob, huh?"