I can see that with the "have you ever done drugs" question, but terrorism or human trafficking? That's quite a stretch. You don't have to ask the question for someone to know that those activities would bar entry. I'd have to see pretty strong evidence to believe that a question like that is going to even give pause to people like that.
Of course no one will answer yes, but if the govt finds out later you did commit a terrorist act, they have the power to boot you out.
In terms of booting them out, the question makes it much easier. If they are a member of a terrorist group and they said “no”, well it’s an open and shut case of lying on an immigration application. If they didn’t ask the question, sure they could still boot them out, but it may be a prolonged process.
Because they have to prove it in court. And the defendant can ask for a lawyers. And then both the cost, and the level of proof required is a lot higher. Will the US have enough time and resources to go to the originating country and inspect all the evidence, check the archives and so on? Probably not for every case.
The alternative they just need to prove they lied on a form and they signed and acknowledged that lying on it means getting kicked out. That's a simple and shut case most of the time.
It seems pointless.
(Not a lawyer nor an immigration expert on US law, though.)
Wouldn't the terrorist act do the trick?
And don't we mostly imprison people forever when they do those?
Of course not. They would lie. And then the US government can then kick them for fraudulently obtaining their citizenship. That's a lot easier and simpler than having to convict them on terrorism charges. So the US government, is doing this assuming they will lie.