I think in the premodern era, you never saw strangers (not like we do). You probably had a pretty good idea who everyone was, and probably knew most people pretty well. If that's even partially true, then although nowadays you might drive past a person on the highway, if your cousin or a lifelong trusted acquaintance asked for help you'd give it. It seems that everyone you saw, esp saw injured or sick, was probably someone you've known your whole life.

You're also heavily discounting the fact that you had to live not only with yourself if you did nothing, but the shame/angst of their family who you definitely lived next door to. TFA is about taking care of "their own", not strangers.