Have you ever caught a cold, and perhaps had a sore throat?
It’s not the cold virus that makes your throat sore—it’s your immune system carpet-bombing the cells that line it.
There will be collateral damage, to be sure—healthy cells wiped out along with those that are infected. But your body’s defence mechanism considers the losses to be acceptable. Or, rather, that is how it is so designed, whether by evolution, or by some other authority.
The point is that, in order to be effective, our immune system also has to be dangerous. Dangerous to us. Indeed, it is even capable of turning on us, as is the case with autoimmune diseases.
Even so, we would not want to be without it—it’s our ticket to living long enough so that we may perpetuate our species.
With that in mind, it would not be unreasonable to suggest that what is good for one system is good for another.
A proven design, as it were.