Although the outside world imposes material limits on our freedom, that has always been the case. First, way back in the day and for eons before it, we struggled to survive; all energy went toward scrounging food and not getting killed. Then came the moment in history when we could start paying alpha male leaders for some modicum of security, but this always comes at a price in terms of what freedoms the alpha males in question are OK with.
So, in accepting that these impositions on our material freedom are an inevitable outcome of our Darwinian origins, what real freedoms do we have left? The big one is cognitive freedom: to be able to think, feel and believe as one chooses. In the US this would seem to be a logical side effect of the freedom of speech, but nowhere in our constitution is any provision about cognitive liberty expressly stated. If it were, we would have a lot more to work with in terms of changing the laws regarding entheogen use.
But all that aside, there is a much more important aspect of freedom: what burdens do we each personally carry that limit what we can do? Personal hangups and insecurities can be a lot more limiting than laws. If you are very interested in pursuing something you believe is worthwhile, but somehow have become convinced that you don't have what it takes, then you are letting a personal hangup have very real limiting effects on your freedom to do as you wish. I think that in reality, finding and conquering these self-imposed shackles is going to buy you more freedom than any campaign to make right the injustices of the world. Although we certainly need people to play that role as well.