To insist that folks with pre-existing conditions who have not been continuously covered by insurance need to be able to buy insurance just like someone who is has been in the system all along is vastly unfair to those who are responsible enough to plan for the likelihood of them getting sick or being in an accident.
People have bee "gaming" ObamaCare by waiting until they get sick to buy insurance.  It is not the government's job to "fix" you after something bad happens if there is a way for you to protect yourself from the financial consequences beforehand.