the major insight of Marx as i have read him so far is that the liberal so-called rights of man (for example, the four freedoms of the free software movement) are concerned entirely with individual rights to do individual things with individual objects (you may run the software, you may study the software, you may share the software, you may modify the software and share your modifications)
as opposed to expressing rights of people *in community*, (for example the right to participate in a software community, the right to have that community take into account your human needs, the right for your work within that community to be free of alienation or exploitation…)
implementing the latter rights would likely require not a freeing of the source code but a controlling of it in an explicitly structured and political manner