No fly lists only affects those that use airlines.
Maybe you missed the part about having your family killed? Like, imagine that your wife is in a car and the cops shoot it up and kill her because they think you're in there. (KKK COINTELPRO case iirc.) The cops. Because of what you said in public. Or having your wife and son killed in front of you by federal agents because you happen to know some racists and wouldn't comply with their entrapment scheme, and the sniper that shot your wife while she was holding your baby is given a medal. (Ruby Ridge.) These things happened in America.
They can't stop you from talking or remove your ability to make speech. I can't be arrested for it either.
Again, technically, they can't. But what if an FBI agent visited you and you spoke to him, telling him the absolute truth, but then the FBI produced a witness saying that you lied about some minor detail? You just "lied" to the FBI. That's 5 years in prison. And even in the unlikely event you manage to beat the rap, the process often IS the punishment.
Take a look at Rodger Stone. He used to be a multimillionaire from a lifetime of hard work and connections. Now he's living in an apartment and most of his money is gone. They want to try him for bogus charges and have him die in prison. Why? He supported Donald Trump. That's not the crime he's charged with, no, but it is the obvious reason he's being charged.
