We can say that for some people because world consist of too many brains and all are different form each other in one and the another way. So for some people country music is the best (like me) and for some country music is good but not the best from all other musics...
And country isnt the worst. It is far from the best in my opinion.
I cant stand a raspy, down south voice as it drives me up the wall. If an artist sounds like they can sing country as well as rock / pop such as lady antebellum or carry Underwood they are fine with me.
While there are quite a lot of great songs across many genres, I personally prefer Rock/Metal, so I have to disagree here. Guys like Johnny Cash and Hank Williams have inspired a lot of rockers over the years, so to say the two are completely independent of one another wouldn't be an accurate statement, either.