Commerce deals with the distribution of value, production with the creation of it. So let's say there is a widget factory. If one person "owns" it and thousands work to make widgets, their production is stolen through ownership, which causes deeper issues beyond the obvious as well.

Commerce doesn't cause problems as it's just resolving a situation of swapping the widgets you made for carrots. Barring some market-twisting forces like the stock market for example, a simple free market where you're happy with the amount of carrots you get for the amount of widgets you get is fine.

The evil of capitalism is not that you can trade. The evil of capitalism is that you go to work, and receive a fraction of the product of your work while someone else who does not work at all receives a lot of it.

Technically the current capitalist western system would be socialist, if employment without ownership would be outlawed, and coops were the enforced norm.

I think the ethical part may have to do with the following from Wikipedia on commerce:

The diversity in the distribution of natural resources, differences of human needs and wants, and division of labour along with comparative advantage are the principal factors that give rise to commercial exchanges.

I do not see how the commercial part is necessary for the distribution of goods though and recognize it as the main culprit in making such a system unethical. I.e., supplying needs is good and necessary, however a commercial platform is not.