Thanks for all the responses so far. I hadn't made the April fool's day connection. Not sure whether it's good or bad timing!
So it sounds like it's not all together a new thing, this general disregard... i've just read Cecil Sharp's Morris Book and although he does comment on the educated classes perhaps not taking such "quaint" traditions of the country folk seriously, he doesn't imply that it's out and out ridiculed.
Maybe it is somehow linked to TV? Whatever, it grates with me - it seems to be singled out among the arts for scorn in a way that i just don't think would be accepted for, say, opera or "world" musics. and it does seem to be a peculiarly English thing.
Not that i'm suggesting that it has to be venerated as wholly serious - of course it's fun too for those who do it and watch it, but i'm not sure that's what the 'outside" commentary is referring to.