Though some women may be forced the majority I know who wear it do it willingly. Let me go into some detail if that is ok.

The Hijab is something both men and women are told to abide by.

For women as you have seen it is a covering of their beauty which the majority of scholars and the majority opinion is cover everything but the face, hands, and feet essentially. That's why you will see women wearing the hijab with long sleeves and pants. There are also other minor things.

For Muslim men it is to cover from navel to knees. At all times other then when with your spouse or alone. Even in death. Another part is to lower your gaze. Basically the first look at a women is forgiven because God is merciful and knows we are human but the looks after that are not. You are supposed to respect women and not "undress them with your eyes".

Now the point of hijab for both Men and Women is to preserve modesty. Basically save your body for your spouse. Why do you want everyone in the world to be able to see your spouses body? Then it isn't that special when you see it right?

If you have any more questions I would be glad to answer.