russian troll 

A person who argues passionately for extreme views, usually without credible sources and often with legitimately fake news. They have no intention to seek truth or represent reality. Their intention is often to pit people against each other, induce fear, and disrupt order, but can also be rooted in the need to be correct despite credible and concrete evidence otherwise. The term is widely acceptable for actual Russian trolls on social media platforms but can also apply to people who don't know or care about how to find credible information sources and /or how to have a civil discussion about opposing views. In an argument they often push a great deal of misinformation, cannot provide sources, are often sensational, and make no effort to listen or understand other's points of views.

I really like hanging out with Karen but when she gets to talking about some subjects she is like a Russian troll; aggressively pushing her point of view with wrong information and no attempt to understand or even listen to others.

russian troll by CLS 8888 July 20, 2018

Russian troll 

What people who believe MSM call you when you say something they disagree with. No attempt to refute or argue the information will be provided, they will just resort straight to name-calling and declare you as a "Russian troll".

Usually these same people will believe that Western MSM uses "fact checkers" etc. too.

Person 1: "Why are US troops even in Syria? Did they ask us to be there?"
Person 2: "OMG STFU so tired of Russian trolls commenting on here it's OMG NO WAI UNREEL!11!"

Russian troll by Hapty212 August 1, 2021