Legal analysis of the “plugins must be GPL’ed” claim

I found an article with a legal analysis of the “plugins must be GPL’d” claim (written by lawyers for a change):

https://www.law.washington.edu/lct/swp/Law/derivative.html

It call such claims “absurd”. It’s a long article but it’s well worth a read.

(My apologies if this has already been discussed here in the past).