This strategy is clever in the short term, given the lines of attack they’re leaning on in the information side of the war.
I rather think it’s based on KGB-style misunderstanding of the liberal mindset: The intended goal seems to be either a) cause overload of the asylum system, distracting the country, and/or b) cause internal division in the country, xenophobes vs. liberals. What they just can’t fathom is, as happened not just in Poland but also with the rest of Europe’s reaction to what the Poles did, c) everyone putting the blame squarely on Russia. Because no matter how much a liberal’s heart may bleed what’s worse is abusing vulnerable people for your bullshit and discouraging that by putting up a hard front is more important than the fucked situation the people themselves are in because the state of the system is more important than random acts of charity. Really, tl;dr: It’s a bad move to negotiate with terrorists. Always.