Unfortunately causing damage is almost always much easier than protecting against it. For a deadly virus this seems especially true because someone could have a lab in their garage and die once it’s created, but to study it afterward would require extreme care.

So say a few bastards release 1000 variants of different super-viruses instead of just one. Then the research and infrastructure needed to counter them multiply potentially to an unrealistic level.

Also if someone can create super-ebola, that doesn’t mean a vaccine could also be created.