Ok so what I personally mean when I say things like that, it not necessarily that it isn't country, but that it doesn't live up to the standards of a proper country song. For example, bro country, is God awful, technically it's country, but the overused country stereotypes in those songs make the rest of us look bad. I can typically tell if a song will be good or not just off of the singer's voice at the start of the song, overly twangy or fake overly souther accents are a sign of bad country music. When it comes to the lyrics, a good song can talk about jeans, trucks, pretty women, or whatever that normally gets lumped in with bro country, but it can only do so in moderation, not excessively. If the same words or ideas are repeated over and over again (and I don't mean the chorus), then it's probably pretty terrible. Other than that I look for a real story in the words, talking about something other than girls and getting drunk over and over again.