It’s kind of like the exposure on a photograph where there are some extremely bright spots, as bright as the sun. If you set the exposure to not clip those bright spots, you won’t be able to see the rest of the photo. Due to not being able to find a scale that faithfully reproduced the entire dynamic range (without visually equating population mountains to population plains), some clipping had to occur; a compromise. We could clip the few outliers using a standard statistical convention and retain the highs, mids, and lows that make up the rest of the image, or keep the statistical outliers and end up clipping pretty much everything else as a result. I included both renditions.

You’re correct that I didn’t say the overexposed graph is misleading. Neither graph is wrong, they both tell truths.

An article could probably be written about the one you’re inquiring about, that discusses how Los Angeles County, Cook County, and ~eight other counties are unlike any other county in the US in terms of population. Completely in a league of their own. As distant as they are, they may be more alike with each other than the counties surrounding them.

But there is also a lot of information to be gleaned from the photograph with the upper fence that leaves the non-outliers within gamut.