Barcelona Reporter links to this horror story on US Immigration's treatment of a tourist from Barcelona at the Seattle airport. Immigration is notorious for being unpleasant to foreign visitors, but all bureaucrats, who universally consider themselves overworked and underpaid, are capable of being major jerks. This seems like a typical bureaucratic screwup to me. Another factor, of course, is that the US receives something like 50 million tourists a year, and some small percentage of people is bound to be mistreated. None of this makes it OK, of course.
For some perspective on the issue, watch this video.