What genre something belongs to and how good it is are unrelated questions. Saying the difference between folk songs and pop songs is that folk songs are better is just going to make you look an idiot if you're trying persuade people to listen to folk music.

It also make you an embarrassment to anybody else today who is trying to get people to listen to folk music of some sort. "Before you can appreciate what I'm trying to get you to listen to, you have to agree with me that Ed Sheeran is crap" - fuck that.