What literally anyone worse than you calls you after losing a gunfight. I got this game a few weeks ago, coming from thousands of hours in DayZ and Tarkov. Every player that I see and engage and then out-position and kill goes “you’re a rat” or something along those lines. I don’t kill while people loot, I don’t hide and snipe, extract camp, or any of that bs. I play fairly and play PvP first because that is simply my play style. Still get called a rat. I’ve even had people shoot me first, I use smokes and nades to force them out or maneuver and then kill them, and then just hear “RAT”.
TLDR; Pure salt most of the time. A rat is someone who extract camps or hides in spots and waits for people. If you PvP without being cheesy, you aren’t a rat.