The shark can not be blamed for being a shark. When we do things like swim in the ocean or even drive a car, we know that there is some risk involved. There might be a chance that we could drowned or get into a car wreck. We assume the risk when we continue with these activities. The shark is being a shark. It didn't attack out of hate or malice. It is called common sense.
Humans have been taking over animal's habitats since the beginning of human existence. If a human gets bit or attacked by any animal, it is their own fault. Animals are only doing what is natural to them. If something new comes into their territory that looks like it might be threatening or prey, chances are they will get fearful and run, or try to attack. For this reason, I do not think animals should be held accountable for attacks on humans in the animal's current or past territory.
Of course it's not the shark's fault. But it's not the swimmer's fault either.
But fault is not what is important here. What's important is what we can and can not do and what is in our best interests. Every species looks out for its own first and humans should be no exception. I'm not saying we shouldn't try to maintain other species as existing. However, taking precautions to drive sharks out of waters where we swim (and I'm sure there are technologies that can be employed in such a way) would be in our best interests to protect people.
I feel that although you take the risk when you swim in the Ocean that it is never your fault if something happens. Tons of people swim in the ocean every day and there are such a small amount of people who get bitten. I think you can not blame the shark though either because that is just what is natural to them.
In the world, there are always conflicts and fighting between animals of different species, so it cannot be said that it is the swimmer's fault for being biting by the shark. The sharks prey on many animals that live in the same habitat. When there is a hierarchy on the food chain, there will always be attacks.