" Open source is a development methodology; free software is a social movement. For the free software movement, free software is an ethical imperative, because only free software respects the users' freedom. By contrast, the philosophy of open source considers issues in terms of how to make software "better"---in a practical sense only. It says that nonfree software is an inferior solution to the practical problem at hand. For the free software movement, however, nonfree software is a social problem, and the solution is to stop using it and move to free software."
https://www.gnu.org/philosophy/open-source-misses-the-point.html