When you have a pharma patent system, it creates a strong incentive to do things like engineer a bio weapon, that only they sell the patented cure for (sound familiar?). Or, push non patented cures and remedies out of the market, via things like import controls and government regulations. Or even worse, try to engineer germs and infections that develop resistance to the current medicines, so they can push new patented ones.
Even if half the world didn't have pharma patents, the pharma patent system incentives behaviors that can cause infections diseases to spread out of control and cause a huge amount of harm.
They put a chain around our neck as a species by locking innovation up. We'd probably, technology wise, be 50-100 years more advanced in pretty much every field if not for patents. It is only the responsibility of IP owner to protect their property, not everyone else.