Disclaimer: I'm an Australian in the US on a work visa.

I'd consider it "not ridiculous" if the vetting was limited to ensuring:

- That my visa application is valid: If I'm coming to work, I'm doing it for a real job and I really do have all the necessary qualifications and my travel plans match my intent.

- That I'm likely to leave the US. I think it's fine to ask whether I have ties to my home country or to the US and whether I've broken the terms of another visa.

- That I'm not already a criminal. It'd be fine to be asked for a police report.

I consider the following ridiculous:

- Anything related to potential future terrorism. If I wanted to enter the US to kill people, why on earth would I get a visa when I could just cross the border illegally or use a fake passport?

- Compelling disclosure of any information a citizen could deny a police officer who lacked a warrant.

Then again, I understand that the US considers visas to be a privilege and I respect its choice to deny them to whoever it wishes. If it decides I'm not good enough, I'm more than happy to take my economic output elsewhere (and I will if they ever ask for details regarding my online presence).

The 9/11 attackers lived in the US on student visas. Some did pilot training in the US. I believe most of the recent European terrorists have been legally in those countries (and for that matter, the domestic right wing terrorists in the US, and the historical left wing terrorists in Europe)

I'm not sure how many terrorist attacks are done by fugitives. Some stuff is easier to arrange when you have legal status.

Also, cross which border illegally? The Canadian? People who need a visa to enter the US probably need one to enter Canada too.

Most of the European terrorists were even born locally.

I really don't get why getting our Fb accounts is so important, given they already have it (or should, if NSA/CIA did the job they were assigned to).