Probably unpopular opinion but I don't think anyone is owed being cared for, besides by their parents given their role in bringing them into existence. Everybody is living their own life and dealing with everything that includes. My question for people who focus on this is are there people you encounter frequently (coworkers, acquittances, etc.) that you don't give that much attention to? Anyone being honest will say of course, truthfully we give little attention to the majority of people we interact with. Can you guarantee that none of those people feel the same hurt by your lack of care? That's not meant as a criticism of anyone's interactions, just that it's worth taking a bird-eye view removed from the first person egocentric perspective to understand all humans in a society larger than 10 people are going to interact like that with the vast majority of people. I don't know anyone who is friends with the majority of people they interact with or cares about all them on a personal level, that person would be a living saint since it's just not practical.
Additionally, helping or dealing with people with severe mental health like most of us here have is not easy for a typical person. It's incredibly draining and I can't expect anyone else to do so out of the kindness of their heart. The way I view it is when I find one person in life like that, that is more than should be expected.