They may ignore or violate the rights of others. The book recounts a number of attacks on farms, businesses and university research facilities. Some of them are small acts of vandalism. Colo. The ski resort was chosen because extremists said it interfered with habitat for the lynx. The excuse given by extremists for making agriculture a target is that it harms the environment and is cruel to animals.
Extremists also dislike farmers because they are property owners.
Private property is a concept they don't accept. Lately, they have targeted farmers because of misunderstanding about biotech crops. The small number of farmers and lack of public knowledge about agriculture make it easy for extremists to press false claims and accusations. Rather he finds them to be social misfits prejudiced against segments of society they view to be conservative or wealthy. These are not environmentalists wanting to get back to nature, but extremists wanting to get back at society.