There's your problem. Your attitude consists of:
We think that the users want X. A bunch of users have
been asking for Y, but we are going to ignore them because
what "we think" the users want trumps what actual
users are asking for. Oh, and the users that don't like
our attitude are "whiny."
Also, I'm failing to see how splitting information between "spoiler-full" and "spoiler-free" makes your content less encyclopedic, or has any link to Ain't It Cool News.
Overall, your general attitude of putting people down represents Wikipedia in a poor light, represents yourself in a poor light, and generally comes across as very trollish.
 Splitting information into 'spoiler/no-spoiler' means that Wikipedia is going to turn into Ain't It Cool.
 Putting information behind a spoiler warning causes the content to be less encyclopedic.
 The spoiler hiding/warning is 'whiny' (and by extension it's proponents that don't want stories to be spoiled are also whiny).
1. spoilers are inherently opinion - there is no way to dictate neutrally what is and isn't a spoiler, and no referenceable source for such
2. spoilers were superfluous in many cases (a section labeled "Plot" or "Summary" is going to have details of the story in it)
3. a spoiler-warning culture was causing editorial problems: relevant information being removed from articles for being a spoiler, or articles being twisted into weird shapes to herd details into "spoiler" sections
4. the spoiler culture was getting gibberingly stupid (a spoiler warning on "Romeo and Juliet" and "The Three Little Pigs", I shit you not).
The thing I did was remove several thousand spoiler warnings from "Plot" or "Summary" sections, where they were superfluous. When those were gone, the other problems were enough for consensus to reach the death of the spoiler warning.
But let's assume spoiler warnings are a great idea. How would you implement 1. neutrally and verifiably in a manner that was hard to argue with?
2. The fact that a major character dies, is pretty arguably a spoiler. Obviously not for stories so common and/or old that they are tropes (e.g. Romeo and Juliet). Coming back to the example of Breaking Bad Season 5, knowing that a major character dies is probably universally accepted as a spoiler within the first year or so after it airs.
Construct the database, put a useful mechanism on it, crowdsource contributions, sell ads. HN is about doing stuff, after all.
(This is also more likely to achieve your desired result of a usable spoiler mechanism for Wikipedia.)