As someone who was born and spend half of my adult life in this country I can tell you an average Polish person didn't "hate Russians" in general before the recent intensification of the war in Ukraine. Despite the 50+ year occupation of our country and everything that happened during it an average Polish person didn't consider "the Russians" an enemy. No, we considered them mostly victims of their own mafia state regime. Also the common belief was most of Russians go along with the regime because they don't want trouble and only maybe up to 15% are real believers in the idea of imperial/communist(funny how both result in the same thing for the neighbours) Russia and even them were seen as sort of victims of their upbringing/propaganda. In short, no, before Feb 2022 most Polish people didn't "hate Russians". Even shortly after the start of the war this didn't really change much. There was an outpouring of support for Ukraine (despite our own mutual hate - look up Wolyn massacres and Ukrainian collaboration with Nazis) because people saw this war as an obvious parallel between how Russia invaded Poland in September 1939 taking advantage of a 2 week earlier Hitler's attack (in reality there was a secret pact, look up ribbentrop-molotov pact). But still, everyone thought this was what states sometimes do(mostly authoritarian countries, but it happens to democracies too), so just a fact a war happened wasn't enough. But then things changed, when news(and millions of refugees with their own recording on their own personal phones) showed us the atrocities "average Russian" drafted from general population does when given a gun and no law to stop him. Suddenly people in Poland realised of our "grandma's tales" of horrible atrocities done for fun by Russian soldiers 50 years ago weren't exaggerated. They were what happened back then and what happens now. This was very enlightening to the state of mind of an average Russian. If a normal country engages in war like in Iraq and Afghanistan for example rapes and arbitrary killing of civilians is the exception, it's a crime, when Russia engages at war it is policy, it is a gift for soldiers to "have fun" for a week before they go to the front as they are expected to die. Then there are all the mothers, the flies and everyone else in Russia. We expected people would see after few months their sons are dying for nothing, nope, they are all getting good (for Russian standard) money and they support it. A recorder and authenticated phone conversation was recorded between a young soldier and his new wife in Russia (he got drafted after the wedding). In this call she told him how she is "fine with him raping Ukrainians, because rape is not a betrayal, also she hates all of them, and when will all the appliances they looted (microwaves, flat screen TVs, washer) be arriving (they have essentially a courier service between the front and Russia for all of the loot). It is calls like that, and contacts with rare Russian that happens to be in Poland for business or driving a truck trough that made an average Pole hate an ordinary Russian. Not 400 years of attempted conquest (this is what nations do), but what they do when they succeed.