It's a country with very few different people and viewpoints because there's not that many people to form groups. While I certainly would never see a lack of diversity as a general goal for a country, fewer viewpoints to consider significantly reduce the amount of time it takes to get stuff done in governments. The fewer ideals you need to consider, the shorter the debates can be.
A country built up out of immigrants like the USA bring a plethora of viewpoints and cultures, all living inside one general government. This is a valuable source of cultural development and progress but the more groups you have within your borders, the more chances of friction you get and the longer politics should take; there are just more factors to take into account, and that's not necessarily a bad thing.
This word has a long history of being used as a racist dog-whistle in discussions over why the US lacks public services.
It's not a good term to use without clarification.