The point of the bottom field is that the sample is too small to say anything about it. That's why it's cheekily labeled "Who?" instead of "Your next favorite game" which (on the right side) delimits (or at least suggests) when the sample size starts being big enough for the measure to be meaningful.If you exclude the lower part (less than 15% Know by) part of the chart, where you can't read anything.
There should have been two separate charts. Not only for visualization purpose, but also because the "less than 15% Know by" section has a very high variability. The two highest rated games (Rance VI and Megadimension) are actually in that section. Not sure this would stand if more people played them.
The messiness is true but it's mostly a problem in that field, which isn't super important.
(Sengoku) Rance was a meme game for a while on there back before I left the site. Wouldn't be surprised if that has a role in it, too.It's also among the lowest "known" games. Probably had a small handful of people who played and liked it.