That doesn't seem to be strictly true.
It goes against the spirit of "15 words" to insist on strict truth. The merit of the quote lies in the fourth clause.
or they have a common effect you're conditioning on.
That's the big surprise. The point of boiling it down to "15 words" is to pick which subtlety makes it into the shortest formulation.
It goes against the spirit of "15 words" to insist on strict truth.
I would suggest that it goes against the spirit of Judea Pearl's Causality to say things that are false or misleading.
Do note that I actually support the example, despite the problems. I expect that the surrounding context in Pearl's work more than adequately explains the relevant details. What I would object to is any attempt to suppress discussion of the limitations of such claims---so if it was the case that the "spirit of '15 words'" discourages discussion and clarification then I would reject it as inappropriate on this site.
People want to tell everything instead of telling the best 15 words. They want to learn everything instead of the best 15 words. In this thread, instead post the best 15-words from a book you've read recently (or anything else). It has to stand on its own. It's not a summary, the whole value needs to be contained in those words.
I'll start in the comments below.
(Voted by the Schelling study group as the best exercise of the meeting.)