I would argue if you had to paint the GPL with a particular brush it would either be anarchist or possibly (modern) Marxist. Neither are necessarily incompatible with capitalism (in the "free market" sense at least, they are incompatible in the Marxist sense of "employer/employee dichotomy").
The idea is that the GPL empowers users to modify and distribute software rather than enforcing a particular structure of developers and users.
Of course the GPL is not a system of government, so these comparisons are mostly "in spirit". In reality, it's a clever hack to give power to users by abusing the capitalist copyright system (which has historically morphed into a tool for corporations to oppress users).
But the GPL is definitely not communist nor socialist because it has no relationship to government intervention at all (other than relying on copyright laws for its strength). Marx had no interest in governments.
The idea is that the GPL empowers users to modify and distribute software rather than enforcing a particular structure of developers and users.
Of course the GPL is not a system of government, so these comparisons are mostly "in spirit". In reality, it's a clever hack to give power to users by abusing the capitalist copyright system (which has historically morphed into a tool for corporations to oppress users).
But the GPL is definitely not communist nor socialist because it has no relationship to government intervention at all (other than relying on copyright laws for its strength). Marx had no interest in governments.