> Fiat currencies have value because of the law
The law is simply the threat of violence, which is what makes it so distasteful. http://en.wikipedia.org/wiki/Executive_Order_6102
> not some wishy-washy magic agreement that people wake up with
Agreements are voluntary and magical, what's not to like? It's the other stuff that's wishy-washy (involuntary arrangements).
> Tax laws, debt laws, torts, fees, fines, etc. are what create the demand for fiat currencies.
There's no reasons these same things won't work for bitcoin. Private mediation and arbitration already exist that support bitcoin. Things like contracts are built into the bitcoin protocol and will facilitate many of the things you list.
> Bitcoin does not have such a source of demand. It has no particular utility at all; nobody will ever suffer for lack of Bitcoin money.
Pretend the bitcoin market is only used for black market activity, it would still have a large utility. Plenty of people on the market would see one less revenue stream.