By the time they're using these extreme powers to smother dissent, you're fucked. It's game over and your ability to speak out using the first amendment is non-existent.
The very reason why these things should never be allowed, is because the absolute protection of freedom of speech is ultimately the last safeguard against tyranny (before you get to violence anyway).
Why let the guy into my house with a gun and roll the dice on whether he intends to at some point do me harm? That's crazy. We've seen enough really malevolent politicians assume power all over the world and domestically, to know better than to take such chances. History is littered with endless examples, it's at best naive to think America can't suffer the same types of fate.