This is unprecedented. Obviously these people only believe in free speech if it is speech they agree with. I don't think I've ever seen such a flagrant violation of the first amendment.
Never assume they're true Americans honoring the Constitution, prefering a republican form of government, supporting individual liberty, respecting states' rights, or defending the American way. Never.
You are correct. This is a violation because this is members of Congress threatening an organization with law if they don't change their speech/message.
This is not you or me threatening NOT to listen to the Ditzie Chicks.
"Congress shall make no law" is the point of the 1st amendment, and these congresscritters failed miserably.
Is it possible to have the SCOTUS rule on a "threat" intended to stifle free speech or does it have to be a finished law?
I might be wrong but I think I remember them refusing to watch Moore's Farenheit 9/11 at the Democrat Convention and writing a similar letter to the networks and Direct TV when Moore tried to show it the night before the election in 2004. I'm pretty sure they did.