1) You really need to get your self-inflated image of yourself, your locale and your ideology under control. Opposing the celebration of Columbus Day is not a "liberal" thing in and of itself. Period.
2) Oklahoma is FILLED with American Indians ... how on EARTH does this surprise you?
Look at a list of cities that have abolished Columbus Day previously. It's places like Berkley, Seattle, San Francisco, Denver, Minneapolis, liberal strongholds.
South Dakota is the only state to have done so, but it's conservative (maybe not as conservative as Oklahoma, though).
I'm not too surprised at this; there are a lot of Native Americans in Oklahoma. Charles Curtis was from there.
Curtis was from Kansas, but yeah, Oklahoma has a large Native population.