The standard implied by the remark I was commenting on.

I read the original post as being about the ordinary human domain, implying an ordinary human-relative standard of significance.

Literally not caring about other people seems like something you may believe about yourself, but which can't be true.

This is ambiguous in two ways: which other people (few or all), and what sort of valuation (subjunctive revealed preference, some construal of reflective equilibrium)? I suppose it's plausible that for every person, some appeal to empathy would sincerely motivate that person.