I don't understand people's obsession with "trolls".

I'm quite new player (about 3 month in game), I already got somewhat bored to play Co-op vs. Ai, so I'm trying to play PVP from time to time. I don't have time to read walls of "best strategies" and I don't have other games experience, so I still don't know what I'm doing and I'm rather learning on my mistakes. (I didn't quite get the difference between support and duo). Sometimes other players guide me, sometimes they don't care, often they just starting to yell and label me as a "troll". I don't understand the last one. I know, I'm not a good player, but it looks somewhat stupid to assume that everybody around seriously just siting there and purposely trying to lose the game for you. (I saw bots-feeders in Co-op vs Ai, but not in pvp, and that's different.) When people purposely malicious they usually do that in all possible ways, including abusive screaming in chat. I don't do that, I want to win too, but I suck. Others do mistakes too. Ordinary pvp is not "professional bla-bla-bla", no one loses money. It's like playing basketball with random people, sometimes you got skilled teammates, sometimes not. It supposed to be for fun or what? How people even can play when they chatting too much? You can't use abilities if chat is opened. Also, it seems impossible to improve by playing only with bots. [sg-lux-2]