There are even some memes about that.

https://i.imgur.com/VYNTAGb.jpg

My favorite example of a non-zero sum economy is farming. If you plant an acre of wheat, each of those little seeds makes about 50 more. Then you have enough to eat and enough to trade.

Bernie wants to tell me how much to plant and then confiscate the harvest so he can buy votes with it. Bye bye Bernie.

Kid's Law: every advocate of central planning always envisions themselves as THE central planner.

Damn you autocorrect, Kip's law.

In a true zero-sum economy, it would be impossible to ever earn a living because there would be no way to add value to anything. The progressive responds by saying, "that's because profit is theft". Well, if that's true, then not only is everyone who earns a living to buy food to put on the table a thief, but also everyone who sells food is a thief, because they stole the food that they sell, and the person they stole it from in turn stole it from someone else, etc., because actually creating food would be adding value, and everyone knows that's impossible. It's common sense!

And the progressive's solution to this is to... legalize theft. At least for politically favored classes. Everyone else can go jump. The reason progressives think that creating wealth is impossible is because the policies they favor destroy wealth and inhibit the creation of wealth. It's a self-licking ice cream cone.