I was there at the hearing, and I think the summary is pretty far from the true situation.
First, Prof. Gabrynowicz is in the minority in the legal community on this (her response is also to work for international consensus on these issues, which is not going to happen.
Second, the Asteroid Act has been vetted by the State Department (and by a whole bunch of interested parties) and it certainly is in agreement with the Outer Space Treaty of 1967 (even Prof. Gabrynowicz didn't claim otherwise).
Third, all of the space powers appear to be in agreement with the basic principle expressed by the Asteroid Act - that space mining is a lot like deep sea fishing - you can't claim your fishing hole, but you get to keep what you take.
For a more balanced explanation as to why the Act is needed as a US instantiation of the '67 Outer Space Treaty to clarify the rules for US Corporations, see Dean Larson's WSJ Op Ed (or my own take on it).