Linus and Greg KH's reasoning for avoiding lawsuits: https://lists.linuxfoundation.org/pipermail/ksummit-discuss/...
https://www.fsf.org/licensing/enforcement-principles https://sfconservancy.org/copyleft-compliance/principles.htm...
Moreover when GKH and Linus talk about how GPL enforcement has done nothing good, they conveniently leave out the success of WRT enforcement, which caused one of the biggest Linux offshoots, largely based on volunteer work.
Finally, the audacity of saying "let's talk about legal things without lawyers present" is such a typical software engineer thing, just imagine the reaction someone was proposing to talk about kernel programming without any kernel programmers present
Linux itself is not that special - it mostly is a case of right place and right time.