From the Department of Homeland Security report on ecoterrorism:
Among the highlighted organizations, PETA, the Fund for Animals, In Defense of Animals, the New Jersey Animal Rights Alliance, and certain individuals within the HSUS are known or suspected of having financial ties to individuals and groups associated with ecoterrorism.48 In addition to financial ties to ecomilitancy, both HSUS and PETA, or at least individuals within those organizations, have an established record of supporting individuals and/or groups commonly associated with ecoterrorism.
That represents the most accurate statement I've read concerning the terror links of PETA and HSUS. These organizations do NOT themselves engage in terrorist acts and HSUS stays far away from settings in which the organization could be associated with terrorism. For example it has been several years since they officially attended the annual Animal Rights conferences because speakers and groups there, clearly encourage if not actually advocate terrorist acts.
However it is clear reading their publications and statements by leadership that PETA supports the people who DO engage in terrorism (they've given money) and that HSUS is glad that the terrorists are out there.
How 'glad'? Well, if HSUS really didn't like the fact that this stuff goes on, they would condemn terror tactics as strongly as they do dog fighting, maybe even offer rewards for tips leading to arrest and successful prosecution, again, as they do for dog fighting.
HSUS can say 'Oh ... we don't support THAT' all they want but as long as they do nothing to actually discourage it, they're at least passive supporters