I have some trouble considering their "Top 5" in the category of "roots" music. I'll agree that it shows diversity, the closest thing to a "folk" song is David Essig's electric version of a venerable old gospel tune that was a staple of the gospel/blues tradition. I haven't seen David for years, but I was disappointed to hear him selling out good music that badly. He used to be one of my favourite performers from the Toronto-Hamilton area folkies of the early 1970s — helluva guitarist even then.
A couple of the others are good (especially Jenny Whiteley's Dance Till Dawn), but they're modern country, not "roots."
I didn't explore the site too extensively yet, but where is the music of Rick Fielding, Bill Garrett, Terry Tufts, Garnet and Stan Rogers, Stephen Fearing, James Keelaghan or a host of others?