Ah, I see. I don't really agree, because I think the enforced unidirectional data flow is one of the best parts of React, but that's certainly a valid point of view.
I just want to emphasize again that Flux is entirely possible without singletons, and works just as well on the server if you create new instances for every request. Flummox does it, Fluxible does it (at least for stores). It's just a shame Facebook pushed singletons and then everyone followed their lead.