I used to think minimum markup was a scam for making guaranteed money for a politicians favorite companies. But in reality, and you can look up the history of minimum mark-up laws, is that they exist to help prevent monopoly. So a large corporation, which can afford to have short term losses, cannot undercut all its small competitors and put them out of business. Minimum markup laws were originally put into place by popular demand.

What about "leave it to the market" "free market" to decide?
If you believe in monopoly, like the robber barons ... then fine.
Also,
arguments surrounding supposedly "keeping government out of the economy" are a false flag special. Corporations are very different from a regular business. They are legal creations. Corporations exist exactly because of government "interference". Take away government and there is no such thing as a corporation. The corporation is a legal entity.

The politicians currently simply repeat all the same old tired stuff just trying for power; to get elected. Boost their ego.