There is a second part to this article http://crowlspace.com/?p=1070 as well as an article on going beyond the Moon http://crowlspace.com/?p=1070
Before someone asks about this being relevant to Article One Section 8 of the Constitution, this is a private company. They can go where they want.
If NASA, however, wants to be truly compliant, they can always reorganize as a fleet.

SRBs are cheaper, have a higher power density, and now that the Shuttle program is winding down, production capacity is abundant.
Why go with 18 liquid fueled rocket motors?