America's strength and weakness is its wild individualism. Unfortunately, you saw the downside of it.

There are several issues here that could contribute to the reaction.

1. America has a very high crime rate. People are afraid that if they stop to help, it could be a ruse and they would be injured. The serial killer Ted Bundy did something similar by pretending to have a broken limb and ask for help carrying books or a briefcase. The fear of crime in the US explains a lot.

2. We have a weak social safety net compared to say Sweden. If someone collapses on the street in a country with a modern social welfare state, the assumption might be the person has a medical crisis. In the US, because so many of the homeless are mentally ill or addicted, there is the feeling that the person is not in a life-threatening crisis but has a problem that cannot be solved no matter how many times one intervenes.

There are so many homeless addicts and persons with mental illness that the system literally cannot help them all.

There is a huge need to provide housing for such people but it doesn't seem to happen.

3. My maternal grandmother's father died in this way. He was a carpenter, in his work clothes, when he fell on an icy wooden sidewalk and broke a hip. He froze to death because people assumed he was a drunk. He was not. He was a good man, a father who loved his children, and who worked hard to provide for them.