One:

http://www.petoftheday.com/talk/show...threadid=81797

Two:

They have been linked to the Earth Liberation Front and the Animal Liberation Front, two enviro-terrorist groups.

Three:

They are sensationalist and have no consience about what they do, as long as it generates publicity. For example, handing out pamphlets at children's events calling the children's mother killers for serving them meat, their advertisement using Rudy Guiliani on the billboard asking "Got Cancer" , and other thoughtless BS campaigns.

Four:

They are absolutists. They want all animals living in the wild, not as pets, farm animals, or in any other way dependent on a human.

Five:

They appear on the surface to be a genuine charity to help animals, thus reducing the gifts to shelters and other true animal charities.

I could go on further, but those are the main reasons.