Since they can't win any other way
Liberals are accusing conservative groups of trying to silence Farenheit 9/11, but if the promotion breaks the law then yes, they should surely try to stop it.
We have heard over an over again about the violent and angry responses of liberal activists to conservative positions (see Protest Warrior for a collection of encounters with "the enemy" :) ). They try to forcibily silence those they do not agree with since they cannot win in a face-to-face debate.
Now, they are trying to silence one of their own...
State Demos turn to court to block Nader