I'd disagree, I think it is a lot easier to create a virus that wantonly destroys life than it is to create a cure that puts everything back together. I could email out a script that just executes "sudo rm -rf /" on everyone's computer, and it would probably ruin a lot of people's lives.

Additionally, cures by their nature will always lag behind diseases, people won't invest resources curing a disease that doesn't exist. A non-trivial amount of damage would occur before society reacted to the threat.