The theatre had no option for subtitles, and whether you understood or not cannot be generalized broadly. If the film is in English, and that is the only word that goes untranslated, there is a problem.
As for Lorca's politics, it is exceptionally clear from his statements on theatre that after returning from NYC/Cuba he viewed himself as an activist-artist and the battles he took on were entirely conceived as a means of desensitizing the audience and moving them in a progressive direction on the specific topics of gender and sexuality. His plan was that each play should push the envelope a bit further until "in ten years' time" his self-described "impossible play" El Publico which dealt extremely frankly with homosexuality, transsexuality, beastiality and pederasty, woul be "a big hit." Bit of an optimist there, but you get the idea.
The motivations for his assassination were very complex and mixed, and loath as I am to admit it, Dalí was pretty near the mark in his extreme denunciation of the Loyalists opportunistic gross over-simplification of the matter as purely political. However, my biggest complaint is that this very powerful and courageous man gets short-shrift in the portrayal of his post-Dalí life and work across the board. All that seems to interest the author is the "doomed gay love-story" angle between two famous artists, and reducing a great man's tragically short life to his first seriously crappy relationship is deeply disturbing to me.
I'm Victor Marzowicz-Velasquez and I'm here to recruit you.