The State Department travel advisories are not just for Covid-19 rates or pandemics, but designed to cover many situations. A pandemic changes everything. The point of level 4 is simply to indicate that it is NOT recommended to travel there right now. In more normal times it could be for any number of reasons, including crime, political unrest or similar threats.
The primary purpose of the advisories is not to differentiate levels of relative risk specifically for areas where Covid-19 is still circulating above a specified level. If below that level, some jurisdictions, such as Dutch Sint Maarten (level 3) will receive a rating below level 4.
There are other tools available online to weigh the relative risk of Covid-19 in specific jurisdictions, if you decide to travel anyway in spite of the level 4 advisory. Given the nature of the pandemic, they are constantly changing. Here are links to two interactive summaries that I use.
https://www.ctvnews.ca/health/coron...s-rank-against-american-states-1.5051033https://www.ctvnews.ca/health/coron...e-canada-and-other-key-nations-1.4881500
