No country has an obligation to carry the burden of serving and\or integrating an endless stream of immigrants from whatever country or conflict they are running from. That’s to to their decision informed not only by their policies, but also their capabilities. Poland is one of the poorer EU countries already, and Belarus (say Russia) use the situation to make EU either accept them and hold the burden or decline and look like they are baaad. But Russia\Belarus don’t want to hold them themselves and treat them like pests unless they can use them as a weapon against the EU, thus pushing them to the border where they themselves keep them in temporal concentration camps to bully Poland and other bordering countries to accept them.
I want to imagine she thought she does the right thing up intil the end.