Why are Russians portrayed as the bad guys in almost all Hollywood movies? Is this a form of propaganda?

 
No, they are businessmen so they do what they make most money from. To make it easy for themselves they use standard, cookie cutter villains. After WW2 is was often Nazis, and they are still a standard villain to use, but as time passed it became a bit tedious. Some spiced it up with zombie Nazis. For some reason zombie Nazis appears to be guarding a treasure rather than wanting to eat brains.


During the Cold War that was often Russians or other east Europeans for obvious reasons. But in many movies the ordinary Russian was not the enemy, but war mongers on both sides. Like in Spies Like Us (1985).


After the Cold War died off they had a bit of a trouble. They tried on using the British as villains like in Cliffhanger (1993) and Gone in 60 Seconds (2000).


Then for a while they standard villains instead was Arabs (terrorists) and South Americans (drug dealers). Like True Lies (1994).


But then they started protesting that they were always portrayed as villains, but by then the Russian Mafia had become infamous so they could use that. And the advantage was that they could get European actors to play them and they wouldn’t complain about the image. Some even made a career out of faking accents.