Dear Piotr,
You are confusing the idea of "being hopelessly enslaved" with "being happy". They may be related, but the concept is NOT the same. In fact, it is because they ARE happier that they are "hopelessly enslaved".
The concept of "hopelessly enslaved" is due to the fact that they make no attempt to break free of the slavery. Those who feel the oppression will be more likely to do something to try and break free.