This video hinges on what seems to me like a pretty big twist or plot point of an entire movie. Some movies rely on a twist and this video spoiled that totally out of left field. And it's really silly to pretend like people are actively talking about this movie as if it is apart of the zeitgeist like GoT is. You said yourself that it was a top 20 movie from over 5 years ago, so really it is pretty obscure in the grand scheme considering how much media there is out there. Sure, a lot of people have seen it but also a lot of people I'm sure haven't and you can only speculate at the ratio like you did comparing the book followers to the show's.
You said it yourself that those books are best sellers but we should respect people from not being spoiled but somehow you justify that it is okay to spoil a movie just because it is "old" and made "a lot" of money. So does that mean that we are free to spoil anything in here that is not GoT/ASOIAF related if it is over X years old and made Y dollars? Where do you draw the line? This is a GoT sub and I shouldn't have to come in here worrying about other outside media being spoiled.
There are plenty of old shows/movies like the Wire, the Sopranos, and others that are hugely popular and old but I wouldn't go around spoiling major events from it out of left field on a sub that is totally unrelated to either show. If I'm going to start watching a new show that I haven't seen I'm careful to not go onto that particular sub or search anything online particularly about that, if it's a movie I take similar precautions.
People on other sites like YouTube and Facebook make the same excuse that you are making justifying spoiling the books because "OMG the books are so old, learn to read. It's your own fault if you didn't know that Ned died or Robb was betrayed at the Twins, etc..." You are just extending that to frame your argument about how you feel.
What I don't get is why you get upset enough at me for something that I said 12 days ago to comment on it. You aren't adding anything to a discussion that hasn't been active for over a week, you are only starting an argument that is going to go nowhere.
tl:dr - don't tell me how to feel about spoilers.