A lot of this is attributable to the way our society is designed at a high level
With the exception of a tiny number of people in exceptionally autonomous jobs (either working for small organizations or in high-powered roles) both government and corporate bureaucracies optimize everything they can for efficiency and replicability at a massive scale, which means that their processes are ironclad, most people have no ability to make decisions that matter, and caring about the results of those decisions cause them either to break protocols and be punished, or try and fail to create different outcomes under those constraints. Most people are unable to choose a job that does better than this and still support themselves. Thus, most people spend a significant chunk of their life, the part where they're supposed to be the most engaged and alert, under a condition of essentially learned helplessness
Increasingly, people's options are restricted in terms of what they can do outside of work too. A lack of third spaces means that most socialization takes place in your home, your friends' homes, or more realistically, an internet platform that is designed and controlled by the same bureaucratic drives. Digital platforms for things like payments, combined with monopolization of most sectors of the economy, has made commerce involve fewer meaningful choices and salient interactions for the "consumer". Increasing use of digital mediators for other interactions and increasing control exerted by the companies that run these mediators create fewer meaningful choices they can make there, too. People often cite the high degree of convenience of many everyday activities as a quality of life improvement that past humans couldn't imagine. This might be true, but the way it's implemented comes with a tradeoff at every turn with meaningful choices. We have in many contexts traded knowing things and deciding things for having a company do it for us, and I say "we" because this is by and large a tradeoff that most people didn't individually choose
A lot of people get this idea in their head that most people are stupid. But even people who aren't particularly educated or bright have a lot more vibrancy, a lot more ability to care when they have autonomy than even very educated and intelligent people do when they don't, and autonomy is a muscle that can grow with use and atrophy with disuse. The design of modern societies has drastically limited the ability of people to act autonomously, to choose most things that matter, in a ton of contexts that take up most of most people's time. Of course they don't care. But like most systemic issues, this author is so unwilling to consider systemic solutions that even after walking up to the brink of seeming to get that this isn't a problem you can just solve at the ground level by caring yourself, the conclusion is still just that people suck, most of them, but somehow individually. Like many people who think they're surrounded by idiots, the author's one example of someone who "cares" is a literal billionaire who is personally responsible for creating similar immiserating authoritarian conditions in workplaces he runs and for people who use the products of his businesses, a textbook defector who has claimed more autonomy for himself exactly by contributing to the systematic ways in which others are deprived of it. There is no way to solve systemic problems at an individual scale