He said that people who took care of themselves and purchased health care shouldn't be penalized by paying for unhealthy people who didn't buy health care.

The philosophical difference is how some Repubs believe the patients with pre-existing conditions should be handled.
Some, like Rand Paul, believe that forcing health insurance companies to pay for non-customers is idiotic.  That's like  forcing car insurance companies to pay for wrecks by non-customers who don't have insurance.

Instead, there would be pools from either the state or federal gov't to deal with it.  Giving money to insurance companies who then pay hospitals (and take a profit, and charge more to healthy customers) is a terrible way to set up the law.