Without absolute certainty, what do we do? We do the best we can. Injustice is happening now; suffering is happening now. We have choices to make now. To insist on absolute certainty before starting to apply ethics to life decisions is a way of choosing to be amoral.
Talking about freedom, about ethical issues, about responsibilities as well as convenience, is asking people to think about things they might prefer to ignore, such as whether their conduct is ethical. This can trigger discomfort, and some people may simply close their minds to it. It does not follow that we ought to stop talking about these things.
It is hard to write a simple definition of something as varied as hacking, but I think what these activities have in common is playfulness, cleverness, and exploration. Thus, hacking means exploring the limits of what is possible, in a spirit of playful cleverness. Activities that display playful cleverness have "hack value".
I have met bright students in computer science who have never seen the source code of a large program. They may be good at writing small programs, but they can't begin to learn the different skills of writing large ones if they can't see how others have done it.
A hacker is someone who enjoys playful cleverness—not necessarily with computers. The programmers in the old MIT free software community of the 60s and 70s referred to themselves as hackers. Around 1980, journalists who discovered the hacker community mistakenly took the term to mean “security breaker.”
Every decision a person makes stems from the person's values and goals. People can have many different goals and values; fame, profit, love, survival, fun, and freedom, are just some of the goals that a good person might have. When the goal is to help others as well as oneself, we call that idealism. My work on free software is motivated by an idealistic goal: spreading freedom and cooperation. I want to encourage free software to spread, replacing proprietary software that forbids cooperation, and thus make our society better.
For personal reasons, I do not browse the web from my computer. (I also have not net connection much of the time.) To look at page I send mail to a demon which runs wget and mails the page back to me. It is very efficient use of my time, but it is slow in real time.
If the users don't control the program, the program controls the users. With proprietary software, there is always some entity, the "owner" of the program, that controls the program and through it, exercises power over its users. A nonfree program is a yoke, an instrument of unjust power.