Tell me one freedom that does not involve denying freedoms and I'll give you the point. If, however, the only freedom you want is the one to deny freedoms, then, this argument became circular a couple messages back.
Using the GPL you deny no other freedom to your downstream users that that.
"Freedom" is not black and white. Sometimes you need to deny users one freedom in order to give them another. For example, Spotify is a non-free application and it has DRM and lock-in and nasty things like that (no doubt required by the music industry). However, it's completely changed the way I listen to music and given me freedom to listen to more music than I could have done before. I have essentially traded the freedom to tinker for the freedom to listen to music.
you traded your freedom to tinker