I don't understand why Burridan's Ass is a problem for anybody. The argument seems to be "there must be free will because, if there isn't, the ass will starve to death". This is very much the fallacy of adverse consequences.
Furthermore, rationality doesn't preclude the donkey inventing a strategy to break the symmetry. It could say "if I can't make up my mind to choose one of the bales, I'll take a step to the left and then re-evaluate the situation".