I think that Bitcoin is neutral with respect to the "left versus right" debate.

Bitcoin is anti-Keynesianism, and pro austrian economics.

Keynesianism is often associated with the left, but that association is wrong; most governments follow a keynesian policy, whether they are left or right sided.

The debate between right and left is mostly about wealth redistribution, and the size of the government in the economy.
Bitcoin is neutral in this debate; it is perfectly possible to envision a taxation system adapted to Bitcoin (see Falkvinge's article on that:
http://falkvinge.net/2011/05/19/the-information-policy-case-for-flat-tax-and-basic-income/ ).

What Bitcoin does not allow is to create money out of thin air. It is sound money.