Whose propaganda did you suck down blindly?

Chill out a bit, my comment could not have possibly given you the impression that I'm a supporter of capitalism if you had read it carefully. I began my comment by putting forward the capitalist argument for copyright - a steel-man argument - and ended it by debunking it.

Copyright is meant to foster and improve the commons and public domain

You said yourself that copyright establishes art as private property (or "intellectual property" if we're being more precise). That does the opposite of fostering and improving the commons and public domain.

If copyright was not tradeable or transferable

Then it wouldn't be copyright. Copyright is a capitalist construct, not a public good corrupted by capital.