"Critics have claimed it's exaggerated". Okay. You'll note that the only citation to that claim is a political science professor in a political science journal who's asserting that las Casas exaggerated in order to establish a rationale for the Spanish crown to intervene. Even if true? How fucked up did it have to be on-the-ground to make that seem like the right tactic?

Even if I steelman this attempt at an argument to its fullest, "exaggerated" doesn't mean "didn't happen"--if you go actually read the article that Wikipedia page cites, von Vacano does not claim that it's false--and we have other contemporary accounts of the Spanish acts of genocide on Hispaniola alone.

Somewhere in the mid hundreds-of-thousands to a million Taino, depending on which ends of the estimate make sense to you, lived on Hispaniola when the Spanish showed up.

By 1650, they were gone.

I wonder what happened? Maybe it was ghosts.