I genuinely think this is a factor in some ways. 500 years ago, what were people worried about? Their immediate concerns, those of family, and neighbors. Realistically, there was no way to get caught up in the minute-by-minute concerns of people in other cities, other states, other countries, other continents. Things changed more slowly and the only time you heard about about a tragedy was if it was truly enormous - or very local.
Now, there is this constant vying for attention/support/outrage/etc. It's exhausting. People genuinely expect you to care about the back-and-forth between two celebrities you've never met, or some event halfway across the world, or some new thing that released now like literally now.
I think that a lot of people have subconsciously hit their limit. They can't muster the energy needed to genuinely think about or care about a lot of this stuff because they're bombarded with so much of it. And over time, I think that shifts thinking. "Why did I not care when X happened?" leads to "Those people don't matter/are less than human" instead of the real "Because I'm completely exhausted from so much happening".