I went to the US on holiday in 1997 and one of the memories from that trip was how I was treated at customs. Nothing major, but I felt like I was a criminal, with all the questioning. Since then they have added fingerprints and eye scans. I've never been back.
My own government doesn't have my fingerprints or eye scans, so there is no way in hell, I'm giving stuff like that to a foreign country.
If they want to keep tourists out, then they are doing a good job.