You're confusing "being aware of" and "caring about".
Autistic people are acutely aware of "social danger". It's something we deal with every moment of every day since we're old enough to realize we're different. For most, it's a deeply traumatic experience to deal with as a child. And by most, I mean nearly 100%. Common wisdom is that there are no un-traumatized autistic individuals.
> for the most part, the answer is: you don’t, so act accordingly
This tells me you fundamentally do not understand autism. "Act accordingly" is one of the defenses we have to learn. And we learn it totally alone. What behavior is and is not appropriate is one big stochastic experiment that lasts your entire life. We learn to observe people around us, but that's not enough. It's easy to mimic behavior, but we don't get the context or reasoning behind it until we get it wrong.
Knowing how to act accordingly is the core problem in most autistic people's lives. It's incredibly challenging and very dangerous. We have a lifetime of trauma built up around this problem, which makes it extremely stressful to be in a situation where you don't know what to do.