The one time someone called an ambulance on me, I had lain down in the grass in a public park next to the sidewalk. I was walking somewhere and I have respiratory problems. I was having respiratory distress of a sort that doesn't resolve with sitting, but resolves handily if I just lay down for like ten minutes.
The only evidence that that there was a problem was that I was homeless and laying down. I had no collapsed. I was not thrashing about. There was no blood or foaming at the mouth or whatever.
Most likely, the reason they called an ambulance was pure prejudice and fear of approaching me to say "Hey, are you okay? Do you need help?" If I had not been homeless, they probably wouldn't have called an ambulance at all. They probably would have spoken to me to find out if I was in real distress or merely choosing to catch my breath.
An ambulance was also called once when my son laid down on the side of the road to rest while walking cross country. Locals saw strangers in their neighborhood and freaked out and called an ambulance.
In neither scenario was there any evidence of real distress beyond, well, we were obviously poor. The thing they had in common was we were poor and people were afraid to approach us because, obviously, homeless people are all junkies and crazies and will do something violent if you speak to them, I guess.
I spent most of my life middle class. I lived without a car for a number of years before being homeless. When I laid down in the grass to catch my breath while middle class, someone asked me "Are you okay?" rather than dialing 911 to sick the authorities on me. I told them I was fine and waved them on.
The irony: I was much, much sicker that day, having thrown up for 45 minutes in a public bathroom before continuing on my walk. But I was pursuing alternative remedies for my condition and walking was a big part of that and I wanted to be left the hell alone by the medical establishment has informed bluntly that people like me don't get well. So, no, I didn't want to talk a doctor about things that day. I wanted to be left the hell alone to pursue remedies that were working, remedies I was afraid the authorities would interfere with if I had to explain myself to them.
I also threw up in the bushes one day while homeless. An asshole yelled at me out their car window as they passed "Drink too much!" I don't drink. I do have a serious medical condition and sometimes my lunch doesn't stay down long because of it.
No, most people don't give a flying fuck about homeless individuals and their welfare. In most cases, they are just prejudiced assholes looking to fuck with the homeless. That's it.