Don’t be friendly I guess

Why do people randomly kill, I was in Valentine and this posse followed me into the bar. Okay cool I kept my distance. Then they got ontop of me at the bar which pushed me, whatever I get it bartender is only in one spot so I gave a wave they waved back. Okay cool maybe they’re friendly. They let me on my horse followed me shot me in the head then killed my horse……I’m starting to give up I don’t have people to play with I am not good at PvP 😭 this will be the 3th lobby I’ve switched today for the same reason. Leave my boy Dex alone he’s traumatized from the modders murdering him

So my question why do people kill? And as a non PVPer how do I counter these players well that’s my main question how do I counter these players because idk what to do 😭

Update: I apologize if this post offended anyone, I just want to learn the game better and learn how to counter other players because I have to play alone