Death threats are not an acceptable method of expressing your disagreement with someone else's political point of view. I happen to like Dick Armey for his career-long status as a budget hawk, but that is totally irrelevant -- like all Americans, he deserves the ability to express himself without fear of violence. Criticize him if you wish; more to the point, criticize the policies he espouses and offer better alternative if you don't like what he has to say. But death threats are not an acceptable tool of democracy. (It's also not accurate to say that FreedomWorks is a Tea Party organization; it's been around since 1992 in one form or another; the Tea Party movement is a much more recent phenomenon, one which continues to lose coherence in my estimation.)
Nor is it particularly relevant if your choice of victim is someone you would apparently sympathize with -- because if you cross the line into actual violence, well, now you've become an actual criminal and the full weight of the law should be used to respond to you. I don't much care how nice the group you apparently once volunteered for sounds. Knives are not appropriate tools of political discourse.
Words and ideas, folks. Those ought to be sufficiently powerful if they are on the side of the truth.