The article you linked gives the number of 358 German victims
I only used that link to point to the original report that started a whole new joint project of Polish and German scientists looking into that subject. They came up with a much higher number afterwards. The Bloody Sunday is not only restricted to victims in the city, by the way, but also incorparates the surrounding areas as far north as Więcbork Wyrzysk to the west, and Toruń in the east. Nakło was another hotspot for violence against ethnic Germans who had CHOSEN to become Polish citizens and stay in Poland after 1921. Look up "Optanten" to understand the background, unless you know it already.
I'd say we are not that bad.
No comparison to Stalin and Hitler; of course not. But what happened during the ethnic cleansing of Pomerania, Silesia and East Prussia wasn't for the light-hearted either. So many victims. What I'm saying is that Poland or any other nation cannot claim the moral high ground when they committed the same or similar crimes as their hated opponent. "We had the right to bomb Dresden and Hamburg because the Germans did it first", said the Brits. "We had the right to treat Germans civilians like animals and kill hundreds of thousands of them in the process because they did it to us first", claimed the Poles. It's understandable from a human perspective, but go down that path and you will not earn any respect as a nation.
My hope still is that all this sick hatred fades away one day and people will finally get along with each other. Unfortunately, the tide seems to have turned recently. My country is so divided at the moment that liberals and conservatives are pretty much at each others' throat. Germany in the early 1930s comes to mind.
any citizen or politician of a nation-state is basically a nationalist
Read the definition again, especially the part about "to the exclusion or detriment of the interests of other nations." Poles don't give a fu*ck about others at all? No empathy if it's to the advantage of Poland? I'm having a very hard time to believe that.