I'm curious: does not allowing SOPA-supporting companies at YC Demo Day mean the SOPA-supporting companies won't be investing in YC companies? I am not familiar

I'm curious: does not allowing SOPA-supporting companies at YC Demo Day mean the SOPA-supporting companies won't be investing in YC companies? I am not familiar with the process; is this just cutting them out of the very first round, or is something being done to prevent SOPA-supporting companies from investing at all?