I could be wrong but I think the parent comment's point isn't that no one cares, but that the scale of the issue—today and spanning far into the future—isn't presently regarded by people in a proportional manner.

So, people care, but not as much as it seems like they should.

The parent also used the phrase "care more"; they aren't saying people don't care at all, so they acknowledge that people can care about more than one thing at a time.