Free software is (in the sense I'm using in this comment) about Legal
Freedom. Freedom 0 is achieved when it's legal to run something (it's legal
to hack linux-libre and run proprietary firmware with it), it's legal to
study, share, and modify Trisquel.
It is, however, illegal to re-release it (or most of it) as something
proprietary (it's what copyleft is).
It's also illegal to legally apply some freedoms in ATI's proprietary
firmware (can you just call RMS and have him modify it?), which is why it's
considered nonfree.
