The oppression of the indigenous people, as horrible as it was, was pretty much inevitable, so it's not really fair to place the blame on Columbus.
You mean "as horrible as it
still is", I assume? The oppression of the Native American persists to this day. Though really... manifest destiny? I assume that black slavery was just another one of those inevitable and unavoidable periods in history, huh?

Columbus was little more than a con artist, siphoning wealth from the Spanish crown. The world was known to be round at the time, and had been for untold ages. The idea that their was a large continent east of Europe was also not new. Columbus did nothing of significance, as you absolutely cannot discover a land that is already densely inhabited. Hell, he wasn't even the first European to hit North America's shores. The Vikings were all about it in the eleventh century, and even Italy's own Johnathan Cabot made the voyage prior to Columbus.
Columbus deserves plenty of blame, as the published journals of his crew will attest to. He was an absolutely vile man, even
before he decimated entire islands' populations. European fielded censuses show that upward of 90% of the Taino people had been killed only 50 years after Columbus' landing. While the effects of European filth--such as small pox and syphilis--would have been unknown, the inhumane treatment of friendly natives was an altogether different subject. His second voyage to "India" was little more than an invasion, with the intent of appointing himself to power. This resulted in outright slavery and direct genocide. Of course, the Spanish was all about this, given the tributes of gold and cotton they were sure to receive from abroad.
The very notion that America has instituted and celebrated something as awful as "Columbus Day" should tell you everything you need to know about the country. This is a nation that is
proud of its bloody heritage. It celebrates it every October, it carves it into mountains in the sacred Black Hills of South Dakota. A history of lies, theft, broken treaties, and outright genocide. It should be something that every American is ashamed of. Yet it continues this very moment through the corruption of the corrupt Bureau of Indian Affairs.
Columbus gets a national holiday because he was too stupid to find India. We push all of the negativity aside so that we can instead celebrate "European Accomplishment" instead. Well then, I propose that we institute a
Hitler Day. Think about it... Hitler caused the Volkswagen to be created, after all, and the Autobahn. His leadership of Germany led to jet propulsion, significant advances in rocket telemetry, laid the foundation for genetic engineering. Why not celebrate his bona fide accomplishments on behalf of humanity rather than "dwelling" so persistently on the genocidal by-products of his policies?