Thought this was interesting after reading a thread debating this topic.
Revisionists have tried to shrink the definition of the word to mean barbecue cooked in steel closed "pits" similar to the method practiced at modern barbecue competitions, which they call "real" barbecue and which they claim is low and slow, cooked with indirect heat and smoke. In practice, many of them are now cooking with high temperatures and wrapping the meat in foil, which is another culinary method entirely called braising.
When they speak of "real barbecue" they are thinking of the popular style of low and slow smoke roasting as developed in the American South. Alas, they are forgetting that barbecue is practiced around the world in different ways, and that the majority of the public just doesn't agree with them.