Oh come now, every holiday celebrates something it isn't, or has a sordid past behind it. Thanks Giving is basically the same thing as Columbus Day. Pure christian traditions are actually pagan festivals, Christmas is Saturnalia, Valentines day is Juno Februata, Easter is Eostre or the Vernal Equinox. May Day, a public holiday, is Beltane (Celtic/Brit Phallic spring festival) and Walpurgisnacht (witches night). Hitler committed suicide on Walpurgisnacht, and many white supremacists and closet racists in the south this is seen a sort of memorial day, or should I say may day.
There is no "pure" holiday, though some in eastern cultures are close, all are tainted. Columbus day is just another day added to the fold for the religious zealots, bigots, weak minded, and nationalist supremacists to celebrate. The only holidays I celebrate are birthdays within my family and of friends. It keeps things simple, no religion, no nationalism, no ties to a ridiculous outdated calendar systems designed by Greeks, Romans, and Chinese civilizations. Holidays are pointless impersonal traditions, built upon the same long dead cultural remnants before them, as a way of controlling the behaviors of the masses, by giving them a day to observe and how they should behave on that day. Most people don't realize you can be joyous or mournful on any day, no day has more meaning than any other; a day is a day. A programmer could do better and create a "holiday generator", (I would call it Holy Day 2.0), picking a day for everyone to celebrate in a purely random fashion. The celebration of surviving one more trip around the sun from the moment of coming into existence, and congratulating others for surviving the same journey is enough. Celebrate the lives of each other, those you love, and yourself, and if do that, that's all you'll ever need.