aggressive Russian behavior....

Seriously, when we were in Austria and Hungary earlier this year, we kept hearing how they were turning from EU rightward and had formed some kind of alliance with Poland and Slovenia and that they were more aligned with these countries which were far to the right of EU and didn't want any immigrants. From what I heard in these 2 countries, Poland has moved far to the right, much closer to Russia than EU these days. Of course I don't know for sure, but i heard this from 2 different tour guides in 2 separate countries.

I suspect that it's simply the common revolving opinion-- the way we've been doing things for a generation or two isn't working the way we like, so we'll try something else. Often something we've tried in the past that didn't work well enough.

Back and forth. Back and forth...

Given that Russia has invaded and occupied Poland multiple times, most recently in 1939, and occupied the country for decades after 1944.

I imagine they don't much trust Germany either.

None of these nations have a terrifically happy history of peaceful coexistence. But aside from natural gas, I don't see Russia as having much to offer Poland (or Slovenia). Germany, in good times and bad, is the economic powerhouse of Europe, and a chill in relations could well send the Polish economy into a tailspin. Last time I was in Germany (admittedly, a while ago now) there were lots of Polish workers--especially in construction--sending money home to their families. Russia doesn't offer anything like those opportunities.

Besides which, unless things change quite radically, Germany and Poland share hundreds of miles of border. Aside from the Kaliningrad pocket, to get to Russia from Poland you have to cross Belarus, or the Baltic states, or Ukraine.

Of course, they still remember the Katyn massacre

while Soviet troops sat on the other side of the Vistula and did nothing.

And then, of course, the massive purges of Polish resistance fighters by the Russians and their Polish collaborators.

Putin has a lot in common with Stalin, whereas Merkel, much as I favor the Social Democrats, is nothing at all like Hitler. I would hope most Poles would realize that, and I suspect they do.