Ooh, sounds like the booker from Celtic Connections was having a laugh, and deliberately hitting an obvious raw nerve. I suspect it's more of a pragmatic decision than policy alone - and I'm sure a lot of the booking policy of a festival like this is dictated simply by who's available and already on tour at the time - it's far more economical to fill part of someone's existing schedule than to persuade them to your festival for a one-off. Maybe most English acts aim their tour schedules at summer festivals? And most English players (with apologies to Cornish, Northumbrians and Anglo-Scots/Irish everywhere) don't play Celtic music.