Since the comparison is in the air, it's worth noting the big difference between Hurricane Katrina and the botched Obamacare rollout. So here it is: 1,833 people died during Hurricane Katrina.
Obviously, George W. Bush and his administration are not responsible for all of those deaths. A storm's a storm. But let's be very generous to Bush and say that the underlying bad fundamentals are responsible for 95 percent of the damage and the bungled response gets just 5 percent of the blame. That's 91 dead people. How many people have died using HealthCare.gov? I'm pretty sure it's fewer than one. In fact, despite all the problems over 160,000 people have already gotten Medicaid.
None of which is to minimize the extent of the failure here. The administration and the Democratic Party writ large had very high aspirations for the Affordable Care Act, viewing it as a legacy-defining major pillar of the American welfare state that would massively improve the lives of millions of people. If they can't make the basic infrastructure work, none of that will happen and it'll be a huge failing. But even in the worst case, they're not going to get anyone killed. That's a big difference.