The argument that this would hurt legitimate hacking is a bad one. The example given was white hats hacking into e-voting machines. You aren't allowed to break into government buildings to make sure they are secure, it's illegal.
As far as preventative laws go, I don't think they are right but they are widely accepted by most people as right. I'll use one that most people agree with as an example. Drunk driving in and of itself doesn't hurt anyone, and some people can do it their entire lives without ever getting in an accident. But we make it illegal to try and prevent people from killing each other.
Yes you can't break into government buildings to show they are insecure, but you could buy the same kind of door as they have, and show how insecure it is.
I think this is how a lot of the e-voting machine hacks are done.
As far as preventative laws go, I don't think they are right but they are widely accepted by most people as right. I'll use one that most people agree with as an example. Drunk driving in and of itself doesn't hurt anyone, and some people can do it their entire lives without ever getting in an accident. But we make it illegal to try and prevent people from killing each other.