"When I read the premise I thought this might be a touchy subject," he told BBC News. "But it soon became obvious that wasn't what the film is about."
Three and Out, released in the UK on 25 April, tells of a Tube driver who looks for a suicidal person to jump under his train so he can collect compensation.
Drivers' union Aslef has criticised the film for its "insulting" storyline.
Crook, who said he was "very proud" of the British-made movie, said he was "disappointed" people had been "jumping to conclusions".
"They're imagining we've made a very distasteful, bad-taste film, which we haven't," he said while promoting Three and Out in central London.
"Hopefully those people who have objected will go and see it and realise they have got the wrong end of the stick."