Earlier quoted context omitted.
They level out both the upside and the downside. If you can never fire people, you're going to be very very cautious about who you hire in the first place. That makes it much harder to get companies into a bidding war that'll actually raise your wages. I've had a few European teammates, and they usually come to the U.S. because they can make 3-5x what they could in Europe. You'll see that a lot in HN comments, where…
You're assuming that the differences in wages between US and Europe are solely due to labor laws, which is quite a stretch, in my opinion.
How does the parent commenter acknowledging a single factor in a situation lead you to believe that they assume no other contributing factors exist?