I'm saying that she has an obligation, whatever she does, not to think about her society as a pit of crocodiles

If my society is a pit of crocodiles, I want to believe my society is a pit of crocodiles! I'm sure German Jews in the 1930s, or Cambodians intellectuals (or short-sighted people) in the 1970s would agree with me.

Society is affected by its members' perception of it, and if everyone just wanted to maximize safety for themselves and their families... why, that society would be utterly helpless!

Nowadays the standard way of solving coordination/tragedy-of-the-commons problems is through the government; for example Singapore has quality public housings that house 85% of the population and have ethnic quotas to prevent self-segregation.

Singaporeans and Americans probably both want to maximize safety for themselves and their families, but the incentives in Singapore mean that sticking to "people like you" is not as attractive a strategy as it is in the US.