I'll put my hand up, I'm an Englishwoman. And a morris dancer as well.
(from the New Esperance Morris website)
I like, from time to time, to enjoy my own culture and heritage. After all, nobody has any control at all over what race, culture or tribe they are born into; you can reject everything about it to the point of emigrating and becoming a naturalised citizen of somewhere else if you want to, but you were still born in the place you were born, to the parents you were conceived by, and whether they brought you up badly or brilliantly is not something you had any control over, either. The other thing that's important about celebrating a festival, any festival, is that celebrating one doesn't automatically mean despising others. Every human culture has its good points and bad points (I don't define racist organisations or antichoice activist organisations or MRA groups as a human culture any more than Twilight fans or UKIP members or cricketers); we should all allow ourself to enjoy the good bits when the opportunity arises.