I wonder, though, how many of the people who use that excuse think about the fact that it's a class-based insult? Churl (or ceorl) was originally a rank in Anglo-Saxon society, a churl being one notch up from a slave. A little later it became associated with boorish behaviour, following much the same semantic trajectory as "vulgar". To call someone churlish was a bit like calling them a chav.
Actually, thinking about modern knights who wouldn't want to be thought churlish reminds me that knights in mediaeval romance often had to do battle with churls, or carls (their linguistically cognate cousins). The churl was usually a big bloke, half naked but armed perhaps with an axe. Against this, the knight had to take him on with nothing more than a sword, a shield, a mace, an axe, a dagger, a full set of armour, a warhorse, the assistance of a squire, and several years' elite military training. Despite these odds the knight usually emerged victorious - hoorah!
These days, such fights don't need to take place by a ford or in a forest clearing. They are confined to the crania of left-leaning liberals. The Establishment still usually has the best of it, though.