Many of us know that governments can threaten the human rights of software users through censorship and surveillance of the Internet. Many do not realize that the software they run on their home or work computers can be an even worse threat. Thinking of software as "just a tool", they suppose that it obeys them, when in fact it often obeys others instead.
The software running in most computers is non-free, proprietary software: controlled by software companies, not by its users. Users can't check what these programs do, nor prevent them from doing what they don't want. Most people accept this because they have seen no other way, but it is simply wrong to give developers power over the users' computer.