You are conflating revisionism and rewriting. Nobody is trying to say Columbus wasn't an important man. Nor "erase" him from history. An example. Hitler was an important man. Hitler helped guide the design for the Volkswagen Beetle. Nobody wants to ban the Beetle. They still sell the Beetle. And, guess what, nobody wants a national Hitler day. In this case, nobody is trying to erase Columbus from history. History is what it is. People are just realizing that glorifying him is silly at best, revolting at worst.
Also, the term "revisionist history" has recently gotten a weird bad rap in the last 20 years. Revisionism is simply to reexamine history though a modern lens. Yes, "Columbus = bad" is revisionist history. This isn't a bad thing like you seem to think it is. As human civilization improves and advances, we tend to see how silly ethics of the past are. We absolutely should criticize the actions of people in eras past. Revisionism isn't changing the FACTS of history, it's changing the subjective interpretation of history.