To be fair, in most folklore courses in college (I teach them) we wouldn't recommend "debunking" as an approach to Urban Legends. Even Jan Brunvand, who in his popular writing is nothing if not a debunker, says in his more academic writings that the folklorist's job is not to debunk but to analyse and interpret. So a halfway decent folklore course should not turn you into a debunker.

The thing that's good about Snopes is that they lay out their reasoning for you. You don't HAVE to take their word as gospel. You can actually READ their reasoning and decide if you agree with them or not.