Tin Pot
Guru
In my old line of work I met hundreds of rough sleepers, and almost all were in that situation because of their own behaviour. When you did manage to help them access a support service the majority would misbehave in some way and get booted out.
There were some people I met in that situation though genuine happenstance, or (non self inflicted) mental health issues, but they were so exceptional as to be virtually extinct.
My understanding is that the majority of rough sleepers are with mental health issues or drug addiction, or both - and that it's hard to tell where one ends and the other begins.
@Racing roadkill
I think it's relatively easy to spot the difference between rough sleepers and gang/scammers - although again there can be cross over.
The mentally ill generally will not want to talk to you at all, and the junkies you can tell the desperation.
Coordinated beggars are more able to interact like regular people.
@OP
If you feel safe, stop ask how they're doing and wish them well. If the reaction or lack of continues to concern you, contact the authorities as suggested upthread.