“if you had to hurt somebody or intimidate them or kill them, it
would be morally justifiable.” — Dr. J. Vlasak
And it is nutters like this that automatically invalidate their position on animal rights (or any other advocacy fr that matter), in my opinion, for taking such a radical viewpoint. No one has the right to harass, intimidate, threaten, assault, or murder another person in the name of their “cause”. Such people are more akin to fascists, Nazis, Stalinists, Maoists, and Islamists than genuine advocates.
If you can’t state your position reasonably than perhaps it is because your position is the unreasonable one and needs to be reconsidered for its content and approach. As a friend of mine once noted, the “terrorist method of argument doesn’t validate an opinion.”