Wow, I don't usually find myself on this side of the argument, but..
Did you even read what he said?
In a republic, which we are, people have to agree on policy and their representatives vote for what the people who elect them want.
The Overton Window dictates what we can feasibly pass with popularity within a system like ours. Like it or not, the majority of voters' opinions fall within this window, and by definition, what is acceptable for our politicians to run on falls within this window. Also, the Overton window of the US has been shifting right so that actual leftist policies are outside of that window (see how little it takes for someone here to cry about how socialism is ruining everything)
Raising the minimum wage is just inside the left border of the Overton window right now. It's acceptable to talk about and most people with a clear understanding of how poverty works agree that it's a viable solution to remedy one of our nation's biggest problems.
You know it's inside of the window because various states have actually passed those changes. It's acceptable to talk about that happening on a national scale when we can see it work on a state scale.
UBI is so far left of our Overton window that it isn't implemented anywhere here (in the mainland) and can be ridiculed easily, and that's the point.