Asking someone to chair a committee that holds beliefs contrary to yours does not mean they will do a bad job.  You are all assuming because Kennedy is an anti-Vaxer he will not make a good chair.  I submit that being inundated with evidence may well change his mind.  Naive?  Maybe, but don't assume it cannot happen.  

Vaccines have been known to cause autism and have caused severe brain damage in a very few children.  The benefits of vaccinating however far outweigh the risks.  Anti-vaxers are correct when they take a Darwinian approach, not vaccinating will let the fittest survive.  I toyed with not vaccinating, however was not willing to take the risk with my children.