I actually had to watch a video about this group (along with ALF and Earth First), and it had some of the funniest, most idiotic scenes I have ever seen in a documentary. In the one scene I can particularly recall, there was a group of these people sitting around a tree stump screaming and crying about how the "evil lumberjacks" murdered the tree. The teacher, however, pointed out that this was the side that they put on for public consumption.
Overall though, these groups are pretty fucked up, especially Earth First. At least ALF and ELF try to avoid killing people, where as Earth First tries to kill people they consider to be anti-environment.