Or, to be a bit more concrete: People are supporting App.net because they hope it's possible, as a business proposition, to successfully fork a subnetwork away from a major social network. Once we have confidence that this is possible, it feels like we can always do it again. We can fork it as many times as we need to. When the rug gets pulled out from under some of us, as it inevitably will, we'll weave another rug.
The money thing, which you believe is irrelevant, is actually part of the argument here: The more revenue each node in the network is worth, the smaller the size of the sub-network that can profitably be broken off and operated independently.
(Note that there's as yet no evidence that Twitter itself, let alone a subset of Twitter, can be run at a profit.)
By this interpretation, if App.net succeeds at all, Dalton's personal notions of how to run a network will rapidly diminish in relevance. Because, once one App.net succeeds, more will rapidly follow.