Director Agnieszka Holland is accustomed to attacks from the right in Poland, but her latest film, Green Border – about the plight of immigrants on the country’s borders – took things to another level. No sooner had it premiered at last year’s Venice film festival, where it won the special jury prize, than the justice minister, Zbigniew Ziobro, took to social media, comparing it to Nazi propaganda. President Andrzej Duda doubled down, resurrecting a second world war slogan about the gullibility of filmgoers: “Only pigs sit in cinemas.” The film that caused all the fuss is an uncompromising work of...