Do data centers compare to the human population going from 2 billion to 8 billion over the past 100 years? Or, are they just a drop in the ocean?

Oh, they're more than a drop in the ocean for sure. Which doesn't mean there's not other things to address, where population is definitely not the main problematic factor, but consumerism is (and throwaway culture). This kind of whataboutism is fallacious, you can do better.

EDIT: As a small anecdotal point, any new human activity that is measured in GW of power consumption is not a drop in the ocean. Admitted, some of these data centers projects are "only" in the 100s MW scale, but all of this combined is increasing electricity consumption by a vast amount overall.