It says right in the title: no book spoilers. Yours was a book spoiler. The zero-tolerance obviously is a result of people doing exactly what you did. Even then, it can't apply to show spoilers or we couldn't talk about the show.
it says it right in the first post, "This thread is a NO SPOILERS thread. Period."
its not just book spoilers, there have been instances in previous seasons where an episode aired or leaked early. As far as not being able to talk about the show, its pretty obvious the intention is show spoilers are fair game once the respective episode has aired at its normal time.
and the zero-tolerance policy is not the result of posts like mine, but people trying to be clever and making it sound like they're predicting what is going to happen and/or flat out spoil right out without any warning; I used spoiler tags and it was for an example that wouldn't spoil the show.
if a non show spoiler with spoiler tags and fair warning can count (as it should since its clearly stated in the first post "This thread is a NO SPOILERS thread. Period.") I wouldn't bet on an
actual show spoiler being accepted