I think when people consider something required, they either mean they wish it taught in school or have a belief that it is profound enough to recommend to everyone. Like, I have a Marxist-Leninist reading list that I made and linked in my profile, and would love for more people to read it (or, more specifically, the works on it) but I can't beam it into people's heads nor force them to engage with it. I can only recommend it for those who actually want an ML reading list.