I have a Czech acquaintance who grew up under Communism - it annoys him to no end when people assume from his accent that he’s Russian.
Your Czech friend no doubt was required to take Russian in school while walking past Red Army tanks on pedestals.
My Polish priest speaks English as a third language. I get an askance look when I speak Russian to him; their enmity goes back centuries.
I worked with a Hungarian who absolutely hates the Russians and everything about them.
He was forced to learn and speak Russian as it was the official language of the Soviet Union. When he came to the US he worked very hard at losing his accent because most Americans thought he was Russian.
Real nice guy unless someone brought up Russia/Russians.
As an added bonus he’s as conservative as anyone here.