Basing your opinions on movies as to whether they agree with your political beliefs is absolute bullshit.
There are parts where the feature drags, but it's still interesting to see what the film maker does when there is stuff happening. I haven't seen the short version, but I would assume that would be the better version that hopefully cuts a lot of the filler out.
Take a shot every time you see feet.
There are several effective elements in Cannibal Holocaust, like the music and how it was used, (some) good acting, realistic blood and gore effects and good editing.
That being said, any movie that uses real animal cruelty and / or extreme animal violence deserves the lowest score possible. As far as extreme cinema is concerned, I have seen Salò, A Serbian Film and Irréversible; but Cannibal Holocaust is the most offensively trashy of the lot. At least those films don't rely on the gratuitous murder of animals as an excuse for their shock value.
The action, sound design and visual effects are top notch. However, the sound mixing is migraine inducing and borderline horrible. Overlong scenes of exposition happen over and over again and I practically fell asleep for a good 20 minutes somewhere around the half hour mark.
It's by far the most Nolanesque Nolan film he's made and there are scenes where the music and sound effects are so loud that I couldn't understand half of what anyone was saying. It's hard…