A small number of environmental and animal rights groups have stated goals or methods that might be considered "terrorist" -- a willingness to destroy property

A small number of environmental and animal rights groups have stated goals or methods that might be considered "terrorist" -- a willingness to destroy property and harm peoples' livelihoods, to intimidate people into changing their behavior, or even to directly harm those involved in actions they view as detrimental to the environment/animals. It does not surprise me that law enforcement would want to keep tabs on the more extreme elements of the environmental movement, any more than that they'd want to keep tabs on the more extreme elements of any other political or religious movement. (Unfortunately, it can be hard to filter the truly extreme from the loudmouthed-but-harmless, and there has probably been a lot of wasted effort over the years in infiltrating groups and surveilling individuals who weren't at all dangerous.)