I know that if a program director gets many requests from listeners to add a certain song to the station's playlit, then he or she might do that.
The examples we're using seem to be mainly country artists. How does that affect alternative? My take is not much. Why? Because alternative fans are a lot less organized, and the music is more splintered into sub-genres with no consensus. Country is a consensus format. Listeners to alternative aren't motivated as much by non-music concerns as country listeners. So I'd say the Zach Bryan situation, or any similar situation, won't matter to alternative radio.