why do people use the term "modern nation" for some countries but not others?

I hear people using this term in reference to places like the US, Canada, Western European countries, Japan, etc. But aren't ALL countries in the 2017 a "modern nation"? Doesn't the word modern mean 'today' making all countries around today a "modern nation"?

?2017-05-01T05:34:31Z

I have never heard that terminology used.

Are you sure you didn't mean "developed nation?"

?2017-05-01T05:23:50Z

youre an idiot