Honestly, I don't see what's the big deal. It seems understandable to me that some casual consumers of a certain form of entertainment may not care enough to want to purchase and consume the entertainment in its entirety.. but may like a short synopsis of that entertainment.. including its oh-so-secret ending.. to be made available to them.
Mind you, I'll be purchasing and consuming the particular entertainment in question myself this Friday and am therefore not interested in spoilers this time.. but I can see why some people might be.
Also: I completely agree with Yglesias. There are a lot of douchebags out there... particularly among his commenters.