I had a chance to watch this Channel 4 documentary. Very very interesting ... As the title "The Dark Side Of Porn" suggests, the story told in this particular documentary is a dark story, but I found it quite educational still. Also I didn't realize that bestiality / zoophilia isn't exactly new or revolutionary. At least the idea itself was introduced in different cultures, and it's not like this idea was just introduced in the 20th century.
Bestiality is nothing short of disgusting. Yes it has been around for a long long time, but that does not change anything.