Attacking neighbours to grab their land, recources, people has been a common phenomenon until today. Do you remember Yugoslavian wars in 1990s?
That Poland was attacked by its neighbours was nothing unusual. When Poland was strong, she attacked her neighbours too, e.g., Russia in 17th century was almost conquered by the Polish army, and Poles occupied Moscow for over a year.
What was unusual is the fact that a big country in Central Europe allowed its neighbours to dismantle it like a Lego block construction. I am talking about partitions. They took place because over centuries Poland had grown weaker, while her neighbours grew stronger. And the Polish elites did nothing about it. The Polish state was unable to achieve such basic things as a strong regular army paid from the state treasury because it was always empty. The ruling aristocracy and gentry didn`t want to pay taxes in fear of the king`s power becoming too big.
Besides, the industrial development took place in our neighbours` countries, while Poland still remained a rural country. No wonder Poland was unable to produce enough arms to supply the army. Polish soldiers during a few Polish Risings had to use scythes. Against carbines. Later they had to use horse cavalry whereas Germans had tanks in 1939.
1863, the January Uprising, Forging Scythes
History teaches us that a weak country which is unable to defend itself is attacked and devoured by stronger neighbours.
It is good, though, that after being devoured by various predators, Poles refused to be digested by them.