My family is of Italian descent, and I have to say, even if the day were eliminated as a federal holiday, it would still be celebrated in those communities. Maybe we should eliminate it as a federal holiday, so those same people complaining won't also have a paid day-off to come and protest it. ;-)
But, to those who point to Columbus' flaws, the others had flaws, too. If you want to eliminate Columbus Day, you need to eliminate a lot of other federal holidays, too. To err is to be human, and they were all flawed. Gov't employees receive too much time off with pay, anyway.
Columbus' discovery of America is one of the most significant events in history. The knowledge he took back to Europe changed the world.
If nothing else, our Columbus Day holiday is a tribute to that historic event.