Lots of speculation in the media that the DHS habitually haul people off flights if they are suspected of abusing the ESTA/Visa Waiver programme,
Sure, the US authorities ensure certain people don't board flights to the States, for all sorts of reasons. I've been involved in flights subject to delays because of this over the years so I can believe the basic circumstances behind the story - and you're right, you won't get an explanation. However what really made me raise my eyebrows was the claim that this lad was denied boarding in person by someone seemingly claiming to be a US Homeland Security Official, apparently operating in an official capacity/in a customer facing role, at LHR, at the gate........now that
is news to me.