On the contrary, proprietary software is evil. Running on top of a free operating system or deriving from free software under a permissive license (writing "being based on" in both cases is not a good idea: they are significantly different cases) does not make it better or worse.
[Trisquel-users] Re : will you distribute information about lowrisc, an open source cpu beeing made?
I agree. It is sad that the work put into permissively licensed software
often ends up in proprietary software that subjugates its users. But that is
a fact. And that is why I wish developers would favor a copylefted license
(GPL or AGPL preferably). Anyway, software under a permissive license is free
software: it respects the essential freedoms of its users, i.e., it is
ethical.
