"Are tax dollars being used to supplment Katy Perry and other celebrities who are paying to ride into 'space'?"
I don't know, are they?
Virgin Space has been doing tourism launches as well. I doubt much in the way of tax dollars, other than FAA, and local and state taxes to maintain airspace, is involved in either enterprise (at least no more than in any other air- or space-related tourism based industry).
Certainly not to the level of NASA- and DOD-funded launches by SpaceX. But even there, a lot of funding is coming from private enterprise for commercial space launches, I'd venture that more than half of SpaceX revenues are private? Would be interested if you can come up with that data, but then, all 3 players are corporations and don't have the same reporting requirements as public agencies, so those numbers are likely buried.