It's a public safety thing, protecting people from themselves. I don't agree with it but that is their rationale. That and the fact that they don't see a dime of that money and its billions of dollars a year leaving the US for island nations.
The government is a slow moving beast - there are a number of different fronts working to have it licensed and regulated in the US and eventually it probably will be - when that takes place is anybody's guess. I hope it is sooner rather than later, I have thousands of lifetime revenue share players signed up at PartyPoker who can only play play money right now
That is my retirement plan if this ever works out.