Huh, most people do not have time and patience to learn all the differences unless they absolutely have to. Back in northern India anyone from southern state is just South indian , no knowledge about Telugu, Kannadiga, Tamil, Malayali and so on.
Similarly in south India I wouldn't be surprised if a typical local think all North Indians are same butter chicken/paneer eating assholes.
Similarly in south India I wouldn't be surprised if a typical local think all North Indians are same butter chicken/paneer eating assholes.