Where you see nefarious intentions I see someone pursuing their own aesthetics, something that is very admirable and that I think more systems engineers should do. It's obviously not your aesthetic. It's not even really my aesthetic. It's Curtis's. But isn't "radically different from anything that has gone before" just a roundabout way of saying "cool?"
As far as the "cult" goes, I am reminded of that part in Jodorowsky's Dune where he's all "I am looking for my holy warriors!" For any system, whether technological, religious or philosophical to remain living and breathing, it needs its adherents and believers, and I see neither bad intentions nor bad outcomes here. Maybe that's just what happens when you are deep enough in the cult. But the cult is... calm. Cozy, even.
Is that so bad?
There is very rarely any externally visible lock-in. That's not how cults work. Cults work by building a community of people who perceive non-members as the enemy. Urbit builds that community by enticing geeks with the promise of something new and interesting and then keeps them in by leveraging the sunk-cost fallacy (people don't like to admit that all the effort they put into learning Hoon was a waste of time) and all the derision that comes from the outside from people who "don't get it".