If Titanic was some low budget indy film, that would be a fair complaint.
So because it had a high budget and was produced by a big-name studio, that somehow obligates everyone on the internet to have seen it?
Constantly referenced, in the popular zeitgeist for years. Changed movie going for years.
In other words, hype.
This isn't about having a photographic memory for every scene and plot point. (Although if you think you need that to remember the media you've watched. Yikes, hate to be you)
It's about recognizing one still frame from the end of the movie, and a vague description of what happened in that scene. You're doing mental gymnastics to pretend otherwise.
At a certain point it changes from "I haven't watched this so I don't know" to "I am deliberately going out of my way to pretend to not know anything about this"
No, some people just haven't seen it. Or some people saw it over a decade ago and don't remember that seen. You're just being a dick because it makes you feel superior.
That's being a contrarian, that's being culturally blind, that's trying to be a hipster and proud of it.
You're the one being contrarian and pretentious. Nobody is obligated to understand every media reference that you dictate is so famous that everyone should know.