Well, firstly just because you or anyone else derides it, does not at all make it BAD music. The fact that it IS so popular worldwide should make that obvious to you. I'm not keen on trad Jozz, Pop, Rap etc, but they, indeed pretty much ALL genres have their own formula i.e why do so many Folk songs have far too many verses?
Others on here explain the Irish migration link to American Country very well. It satisfies that longing for sounds of home when you're far away, theredore is comforting and warming, plus sad songs have always touched people more than other topics. That you 'don't get it' says more about your lack of musical appreciation than the actual quality of the music. Variety is the spice of life