Well if you're illegally hunting whales with your boat and somebody fucks up your boat, I might no agree with the sentiment of committing a crime to stop other crimes, but I'm not unhappy about the outcome either, not at all actually.
My main concern about them would be that their way of taking action would be actually harmful to the cause, but it seems like their work actually makes a (positive) difference: "By 1980 he'd single-handedly shut down pirate whaling in the North Atlantic..."
Also, their portrayal on Animal Planet is entirely up to the editing of the station, which doesn't want the most accurate representation of what's happening out there, rather the one that sells best. But still, it's making people aware of the issue...