When I see an overfliendly guy saying hello and trying to initiate a small talk with everyone I instantly think that they are either making fun of it or that something is wrong with them. Politeness and openness have their own social cues and when someone just decides to do something for just one day on their life, just because “today say hello people” then it sticks out. You cannot draw conclusions out of it. I would simply just ignore them and look the other way. That doesn’t mean that I would also ignore someone who would truly wanted something
I would ask “who hurt you?” but solitude can be damaging for one’s mental health too. No, seriously, I get the point you want to make but not having talked to any other person for 4 years is not healthy either. It looks like you have internalized a lot of these things that you wrote about and the way you talk about them doesn’t look like you can find whatever you need too.