It's probably because the countries that are ranked lower have even larger and more systemic issues with democracy. Keep in mind that most people in the west and the English-speaking world experience a large reporting bias towards the US (and Europe, etc.), and this compounded with the size of the US means it's very easy to find a new negative story about the US every day.
I don't say this to excuse the problems. I just want to point out (based on my experience with family in some of these places and local news sources there) that the countries that are not ranked as highly tend to have a lot of problems that people who focus on US news genuinely don't often hear about and know about.
I don't say this to excuse the problems. I just want to point out (based on my experience with family in some of these places and local news sources there) that the countries that are not ranked as highly tend to have a lot of problems that people who focus on US news genuinely don't often hear about and know about.