[SkyBelow]

That entirely depends upon the cost of preventing them. At no cost, sure.

But nothing is ever free. So what is the cost.

<insert a villain who determines destroying all life is the best way to stop all future harm>

There is also the consideration of if a crime being a crime is just. Consider crimes that use to be on the book that we now consider horrible things to have outlawed or even crimes that are still on the books but not enforced because we reject them.

For example, some places us to make it a crime for kids to play pinball. Is preventing kids from playing pinball, even if it came at no cost, an unquestionably good thing?

For a sufficiently bad crime, at sufficiently low costs, preventing it is good. But those two factors are both very big questions, directly challenging the notion of "unquestionably good".