Amash obviously isn't talking about abolishing laws against murder, bank robbery, fraud, etc. Those things are all against the law for good reason. Specifically, if I slug somebody in the jaw, I'm harming them (although probably not very much). And just as importantly, I
know I'm harming them and that what I'm doing is wrong -- all of us have a built-in moral intuition that tells us that we shouldn't go around punching people. Those are good laws. All of us who are libertarians, as opposed to anarchists, think that laws like that are great and the state should enforce them.
We have a ton of laws that don't work like that.
In some cases, they're laws that criminalize things that shouldn't be criminalized in the first place. For example, in Indiana
it's still a criminal offense to posses any amount of marijuana. In theory, a kid busted with a joint could get up to a year in year, which is insane. Now, obviously, the typical (white) Hoosier kid who gets caught with a little pot doesn't go to jail, but the fact that such a harsh sentence is hanging over a person's head for committing a harmless offense against an irrational law gives police and prosecutors a lot of power for no particularly well-intentioned reason.
Then you have a whole edifice of laws that exist for the purpose of making it easier to prosecute people who you think might be breaking some other law. For example, say I'm recreational poker player who values his privacy. I don't want to keep my poker winnings under my mattress, so I deposit them in my bank, like a normal person would. But I know that if I deposit $10K or more at a time, the bank will report that transaction to the federal government, and I don't want that because I don't think it's the government's business to keep track of every little thing that I do. So instead of depositing my winnings all at once, I make smaller deposits of $7K-$8K each.
I am now a felon who faces up to five years in federal prison because I deposited my winnings in batches that were too small.
It's probably not a coincidence that the war on drugs and war on terror both generated a bunch of these types of "crimes." They don't harm anybody and they're not even remotely intuitive, but they sure give prosecutors a lot of power.
And then you have a whole assortment of more or less random things that are illegal and (in theory) harshly punished. My go-to example for this sort of thing is
the federal crime of picking a feather up off the ground.
But there are lots of other examples out there. Without knowing the specific context of Gorsuch's remarks, my guess is that he was probably talking about this sort of stuff, although Gorsuch seems to be pretty good on this issue all around.