I usually avoid strangers, because those who talk to you are usually weirdos. Thing is, if normal people don't talk to strangers anymore, then only the weirdos are left, reinforcing the idea that only weirdos talk to strangers...
In my experience, only weirdos never speak to strangers. Social skills are easy, conversations are easy and strangers are just people you don’t know yet. I still can’t understand the point of this. Do you get a charge telling social anxious people they’ll be weird if they do their homework? That’s precisely what you did. Why?
If someone on the street tries to talk to me, I try to avoid even looking at them or acknowledging them. They'll use that as an opening. Just keep walking.