The problem - when you cast your net that wide - is you inevitably catch something you don't want to catch.
Given that you'll never be able to prevent copying, the question is, what can you do to minimize it? What can you do to make consumers happy enough with legitimate use of the system that they'll be willing to pay for it?
Innovation happens because there are people out there doing and trying a lot of different things.
We're in a situation where the solutions that we have are not good enough. The way to improve anything is to have a discussion about its flaws. To understand what the one or two or three things are about it that would help fix it. The DMCA makes it dangerous to have that conversation.
In making policy designed with copyright in mind, you end up making decisions about whether other important technologies, such as privacy-enhancing or file-search technologies, should be encouraged or discouraged. A collision is happening between creativity and protecting IP.