Plan 9 license

[Richard Stallman]

    But the idea that
    information can be stolen already has a strong foothold in the public
    mind, even among the Free Software and Open Source movements. For
    example, I have often heard that one should use a copyleft rather than
    an unrestricted license so that "the source code can't be stolen."

They are using the term "stolen" in a sense which does not refer to
illegality.  Quite the reverse--the action they are calling "stealing"
would be lawful, and that is precisely the point they are making.

So I think that use of "stealing" for this is a misleading analogy,
and will lead to unclear thinking.  We should discourage it.

Legally, making a non-free version of a copylefted program is a
violation of the copyright holder's rights.  But morally, the wrong is
not done to the program's author.  It is done to the public.