If anything, we should be encouraging Columbus Day. It serves as a reminder of our nations founding.
Uh Columbus not only had nothing to do with the founding of the United States (nor did he ever set foot in any modern day US territory), but he predated the founding of the US by a greater time than the Declaration of Independence predates the present day.
It was founded long before the declaration of independence was signed
That makes no sense at all and Columbus never even VISITED modern US territory.
Which, in turn, begs the question as to how 'Columbus Day' can possibly be considered offensive to anyone in the modern day United States given that he never (most likely) harmed a hair on the head of any ancestor of anybody alive in the United States today. Unless, of course, one regards the 'native' populations of the Americas as some kind of homogenous hive-mind, which is an... interesting idea I suppose...
Ummm...you do realize that Puerto Rico exists right? Not to mention the fact that Dominicans are the largest ethnic group in NYC.