That is an interesting video. On the one hand, it is interesting that enjoyment value might be higher for those who have a plot spoiled; on the other, there is something to be said for authorial intent. The other day I finally watched Gone Girl, having zero idea what the movie was about. My enjoyment of that movie was based on not knowing what was going to happen; I don't think having it spoiled would have made that a better experience. Maybe the general populace is just to lazy or impatient to enjoy quality story telling. :p

That said, movies involve a passive audience. As an extreme example, would it be fun to solve a puzzle with spoilers? Like, if you saw the answers to a crossword puzzle before you started it, would that actually be an entertaining experience?

This may just be a culture shift. Those of us who started with tabletop gaming didn't have walkthroughs to consult before entering a dungeon, so much of the magic of gaming involved exploration without helps.