I don't like the idea of having people flying around with no medical doing something incredibly stupid and getting GA shut down for all of us.
Not to pick a fight, but can you point out any significant differences in the crash rates between sport pilots and private pilots directly attributable to the lack of medical certification? I had a lot of the same concerns when the proposal for sport pilot was put forth but those have largely never been supported by the actual events that have transpired.

As for LSA getting GA shut down for all of us, if the suicidal pilot punching a hole in the IRS office didn't do that, the only thing that is going to do it is if we thumb our nose at the NTSB and FAA over the recent issues raised regarding our crash rate. You drop the body count through both prevention efforts and survivability improvements (which are most easily accomplished in the experimental category because of our leeway) and you drop back off the NTSB's scopes.