The vexed question of where the boundary lies between environmental activism and terrorism (thoughtfully explored in the documentary If A Tree Falls in the recent film festival) gets the once-over-lightly here.
It's a shame, since Watson, founder of the Sea Shepherd Conservation Society, is the embodiment of one extreme on the pacifist/activist spectrum.
He dismisses Greenpeace as "the Avon ladies" of environmental activism ("Taking pictures and hanging banners isn't going to change anything"); old colleagues describe him variously as the Rambo and the pitbull terrier of the business.
The burly, bearded Watson is a familiar figure in this neck of the woods, having headed up many summers of raids on the Japanese whaling fleet in the Southern Ocean. The Ady Gil, which sunk after colliding with the Shonan Maru 2 in January 2010, was a Sea Shepherd vessel, but the group has given as good as it gets: Watson scuttled two Icelandic whalers in harbour and has a ramming manoeuvre he calls "Operation Asshole", after the angle of approach.
But despite its title, this film doesn't take us far in understanding him as an individual - he's plainly angry at his dad - and does little by way of challenging him to explain his dedication to aggressive, not to say violent, action. Largely, one suspects, that's down to the man whose blunt, even arrogant, approach has earned him admirers and detractors in equal numbers, along with a large bunch of celebrity supporters.
