Copyleft licenses are oppressing someone

I go to a party, carrying two expensive bottles of liquor that I have acquired from faraway lands.

The hosts of the party provide a variety of liquors, snacks, and mixers.

Some neuro guy shows up, looks around, feels guilty, says that he should have brought something.

His friend shows up, bearing hot food. The neuro guy decides to contribute $7 to the purchase of food since he didn't bring anything. The friend then proceeds to charge us each $7.

No one else demands money for any of the other things being share and consumed by everyone. The hosts do not retroactively charge a cover fee for entrance to the house. No one else offers to pay anyone for anything.

The neuro guy attempts to wash some dishes before leaving, but is stopped by the hosts, because he is a guest.