Yeah, but the other empires on the list are (obviously) guilty of imperialism, too. And considering how less historically literate meme-goers would ask why they're ranked as they are, I'd assume that pointing out how Tsarist Russia once had the largest contiguous land empire (sans the Mongols) wouldn't be a good look, either.
That, and it's a little weird to me how your post places the US having a fourth of the world's industrial capacity in the early twentieth century in the same category as British colonialism, though given how pointing that out would rile people of a certain political persuasion (read: the MAGA base) up, anyway, well...