Whether the film is Pro, Con or Neutral, I believe, as stated above, that showing a film about this film will only glorify these men in a sick way... people latch onto because of it's disturbing nature, and there are A LOT of 'copy cats' out there.
Look at human serial killers, and how the most prominant ones had 'copy-cats'. A lot of people where murdered just because someone wanted to mimic another's actions... Why? Who knows, but I believe making a documentary will not serve any useful purpose. If there is one, let me know; I sure wouldn't want to keep going thinking that this animal died in vain...