Some of you appear to have been a little carried away by your posts on this subject.
Security officials interviewing passengers have absolutely nothing to do with one poster who mentioned a so-called "illegally elected president." Comments like that should belong on another forums and not one linked with the serious business of aviation.
There is also no animosity between the U.S. and British governments, so therefore, you can scratch that as a political motive.
With all the intelligence information flowing in that the bad guys might make a move over the holidays, you can understand that everyone is skittish. It was the Brits who cancelled the next day's flight to IAD.
Wouldn't you rather be on the safe side than on the sorry side?