If you are referring to Germany 1936, it did not resembled modern western democracies at all. It was not established democracy at all prior. It was forced into democracy it never wanted after loosing war. Prior, it was heavily militarized some-constitutional monarchy. Their democracy was failing mess the whole time.
If you are referring to something else, be concrete.
I'm comparing Germanys "helpful" occupations of neighboring countries "to help the poor Germans there against abuse" inhabitants to Putin's attempt to occupy Ukraine "to protect all the poor Russians there against genocide."
Well, there were Danzig (a free city state) and Königsberg. Not that I would consider that being a reason to invade anyone so. Unless you are a crazed war monger in search of an excuse.
Tho, Germans did tried to create local nazi guerillas in northern countries that would support them from inside. It did not really worked out, they never got numbers.
In all fairness, unlike Poland in 1939, Ukraine is not a country that managed to wage war against almost every single of their neighbours in the 20 years before the bigger fish came taking a bite.
That doesn't make Hitler any less a criminal - it just explains how his casus belli sounded more believable back in the day.
If we are comparing history, let's get the whole picture.
Hitler was actually quite open about his "conquest for living space" project and goals. It was believable only if you wanted to believe and afaik, they did not believed him at the time.
They mostly thought they are not ready for the full scale war yet, but that is different calculation.
Pretty funny how open people sometimes are about intentions and goals, and still nobody believes them. Personally, I think people like Xi and Putin can be taken, when it comes to strategic goals, taken by their word. Which is scary in itself, also scary that nobody seems to do exactly that.
Hitler's casus belli was already bullshit back the day. And the whole East of Europe, from the eastern border of Germany to the Russian pacific coast was at war following WW1. With quite a lot of external intervention I might add.
If you are referring to something else, be concrete.