You have heard of this open source thing, right? I don't think that you can argue that the open source ethos has anything to do with capitalism. In fact, I would say that Stallman's views on software are pretty overtly communist, as they contest the very concept of private ownership of a piece of software.
If stall man really believes nobody can own software, then stallman believes that all programmers should be slaves, unable to profit from their own labor.
As Stallman deemed it impractical in the short term to eliminate current copyright law and the wrongs he perceived it perpetuated, he decided to work within the framework of existing law; he created his own copyright license, the Emacs General Public License,[8] the first copyleft license.
There is nothing that keeps an open source developer from profiting from their labor. Some are employed by a company explicitly to work on OSS, or contract with a company to implement a desired feature. In fact, an open source developer can _only_ profit from their labor, and not at all from their "capital".