I never understood the need to worry over who watches what and what they haven’t watched. It doesn’t effect me and it’s completely easy to understand that not everyone likes older movies without creating a thread over it or lamenting the state of “normies”
People maybe shouldn't worry about the average viewing habits of any particular individual walking down the street. So, no, I wouldn't go up to someone waiting at a traffic light and say 'hey fukface, you seen any Cassavetes' (well, at least not often). But I think it's just fine to worry about general trends of what people are, and maybe more importantly, aren't watching. They mean something. They tell us a lot about what people think about art and the place they put it in their lives and what films might continue to be recognized for years, and which ones are going to be eventually completely forgotten (rightfully or wrongfully)
Also, conversationally, especially in a place like an internet forum where people are specifically coming to talk about a specific thing, ya, it can also be annoying when there are these giant and constant gaps of knowledge to contend with in basic conversations. Maybe that's petty, but it's still annoying. If I went to shoot the shit in a forum where they talk about history, and if someone asked about my opinion on something regarding Europe, and my response was "I don't do Europe", it would be completely understandable if they wanted to bludgeon me to death with eyeroll emojis.
Also, let's not overlook the importance of not letting swaths of film history fall by the wayside because it's old. That should be something anyone who cares about film should be anxious about to some degree, especially when it is such a common trend (and frankly always has been) for each successive generation to shun the art that came from those generations before them. I want as many of these older movies to be seen as possible. I want as many of them to find as many fans as they possibly can, even after everyone involved in their creation is long dead. I want to believe art isn't simply something that speaks to one generation of people and then becomes obsolete. It's at its best when it speaks to us from across decades or even centuries. And when we see people throwing up their arms when asked if they have seen anything from before they were born, as if it was the dumbest thing they could have been asked, I worry that not much can possibly survive that kind of apathy for very long.