It's not puzzling. It's ubiquitous.
You go into a waiting room and they have the news on. You're listening to the radio and they constantly give news updates, even on the music stations. It's not all political news but it's still impactful. Even if someone minimizes their personal engagement with the news, the people around them are still consuming it and bringing to the forefront of conversation.
Social media is the same. We can all look down our noses at it but it's a huge driver of social information and people are social. I'll use 2 anecdotes to illustrate how older people simply do not understand how this works for the younger generations.
First, my business partner has a kid. The kid plays video games with his friends. But many of the games they play are online so they talk while they game. So, one kid starts making fun of another kid in the video game chat but the kid being mocked isn't online playing the game, so he doesn't know. Then that mockery goes from the game to a social media platform. Now the kid being mocked is being made fun of by kids he doesn't he even know. And the spread is almost instantaneous because social media. When he goes back to school the next day, he finds himself being mocked by a large contingent of people for reasons that he has no idea about. Why? Because the mockery started on social media but it moved into real life. We didn't have to deal with that growing up, if someone was making fun of you, you either knew who they were or their reach was only their close friends. Now, that reach is everyone with access to that social media account. How does a young person manage that effect? Even if they are not on social media themselves it's going to have a massive impact on their social standing, their sense of self, etc. It's a completely different world.
Second story, I have a friend at my kid's school (smart guy, runs a hedge fund, used to a pretty good athlete so a well rounded normal human). Put his foot down on social media. Complete no go in his house until the kid is 16. But then in middle school, the school organized a dance. Kid needed a date. Problem was, everyone was asking people out on social media. All of the plans about meeting up to get there or what to do afterwards were happening on social media. By not being on social media, his kid was being locked out of the social world for his age group which is horrible for kids at that age. So, he had to choose between his adult opinion on not letting his kid have social media and the kid's social health from being ostracized. Tough balance but he had to accept that he couldn't run a complete ban on social media and still have a socially healthy child. He struck a compromise but the end result is still that the kid is now somewhat exposed to social media...because it has become an essential part of this generation's living and life, for good and for ill.
Our generation gets to pretend that it's easily ignored because all of our similar aged friends grew up in the same way. Either social media was brand new and not what it is now or, for the older people, they went through their formative years and social media didn't even exist. Either way, none of us have the requisite experience to honestly say that this generation can just ignore it like we're choosing.