Ironically, I can't really get into detailed discussion right now because I'm literally walking to my social psych class I teach, lol.

To the first point though, take a step back and understand that more recent studies have shown empathy to be the normative state of humans. Humans, like most pack animals, need strong intuition and empathy to survive with both their own tribe and others.

That has limitations, of course, as we're most empathetic to people we identify with or find similarities to. People fight for their kin, not necessarily their neighbor.

I recall a study... I forget the name (author name sounds like Nier) but they found that folks even cooperated more when wearing similar sports paraphernalia, even bridging racial divides. The stakes weren't huge; just signing a petition, but you can't necessarily ask for more from an academic paper.

As to the point of being on offense, that's probably outside the realm of social psych but I'll try with what I know. I know helping behaviors tend to get stronger when people feel they have the agency to do so. Studies are quite a bit more tame than taking arms or something, but the Good Samaritan study kinda shows this. People running late aren't willing to help someone clearly in need, but people running early are. Imagine the parallel to society-- who has the money, the time, and the energy to help?

Edit: the comment on walking to class is real and not a flex, btw. T-minus 15 min now, though it's only undergrad and we're teaching love and friendship today, which is totally unrelated, lol.