The refusal would have been worded along these lines “your presence in the United Kingdom is not conducive to the public good” Personally I think Immigration officers (thanks to the bed wetters and lawyers) use this refusal far too infequently. However in this case they got away with it because the guy is white. Had he been a (c)rapper who glorified violence and rape etc. he would have been let in. There was a case not that long ago where some American (c)rap singer was initially refused entry, but allowed in on appeal. The US has a similar process btw they ask if you have ever commited any acts of moral turpitude.
http://en.wikipedia.org/wiki/Moral_turpitude