Maybe GPL started as an anti-capitalist license, but in practice it became very much pro-capitalist. It got to the point that GPLv3 and AGPLv3 were split into two licenses to satisfy capitalists.
Among various properly written and practical open source licenses Parity license is probably the most anti-capitalist one.
Among various properly written and practical open source licenses Parity license is probably the most anti-capitalist one.