If you are not free to voice your thoughts, and listen to others voice theirs, you’ll never grow, progress, or learn.
When you stifle speech, you’re inhibiting the ability to think. You become an unquestioning robot, churning out the ‘correct’ opinions you’re required to have that involve no deeper thought or introspection or understanding on your part. Why do you believe the things you believe? Can you defend your positions, or is it because someone told you that those are the correct opinions to hold?
If you’re not free to speak, in what way are you a free human being? What makes a human being unique other than their mind?