Two swallows don't make a summer ....
I don't think that hobby beekeepers should be discouraged from going treatment free - I've been treatment free since day one and I'm a hobby beekeeper. It's not a path (in hindsight) that I would recommend for a new beekeeper but get a couple of years under your belt - learn the craft and understand your bees (and TF does require some additional effort) and it does not always result in colonies that die out. There are a lot of variables that will govern success or failure as long as you know what to look for in a colony it's feasible. What's the worst that can happen ? You find a colony that continually gets infested and is weakened by varroa ... if it happens you treat and watch the other colonies. If you get lucky and the bees, your surroundings and the general mix of how you look after them result in a colony that survives and thrives without treatment ... it's good. As I've said many times - it's not a path to tread lightly, there are risks and I'm not evangelistic ... but if you want to try - try.