I know it seems difficult to distinguish but Poles do distinguish between the Russian people (who also suffered terribly under the Tsar and hte communists) and the Russian (or rather Moscowite) political system
And, yes, they can never forgive Katyń -- or the Nazis. On 1 August at 5 pm here there is the anniversary of the Warsaw Uprising and everything and everyone in the city will stop for 2 minutes.
I even see teenagers putting the PW sign and Pamiętamy graffiti ("we remember") everywhere.
Katyń was a Muscowite aim to kill off the Polish intelligentsia and make the Poles as subservient as the Russian people were (Russia had been under tyrannical rule since the Mongols - the Muscowites inherited that) -- but they couldn't cow down the Polish spirit (there's a joke that if there are two poles there are 3 opinions and 5 political parties) -- Stalin himself said that to put communism on Poland is like putting a saddle on a cow
but in a way the sacrifice of the Poles ensured that communism would fall -- because Stalin was correct -- communism crumbled in Poland due to Pope John Paul II and Solidarność (Solidarity). They started it in 1979 and that ended with the collapse of the Soviet Union in 1991.
Poland with it's boisterous democracy which it has had for centuries is at complete contrast to the autocracy of Muscowy. THAT is the root of the dispute between Muscowy and Poland and there is no way to get around that...
Not the Poles I met, here in America and they were recent immigrants. They expressed no love of Russians to me.