Well- you're going to hear this.
How many women do you think would CHOOSE to obscure their humanity totally, or suffer in layers of clothing, if there were not an element of FEAR involved?
The fear of physical punishment and/or death is very real for some of these women. We can't know how much of their attire is 'chosen' because of 'modesty' until the intimidation and fear is removed as a factor.
With all the reports of family members actually killing their wives/daughters/sisters etc for 'immodest behavior' why do you insist that modesty-not fear- is the motivation for most Muslim women?
Even those who think they choose because of 'modesty' have been programmed to think that way. Psychological oppression, cultural pressure and group-think all play a part in what choices they think they have and are 'free' to make.
The thing is, they do not choose modesty.
In many cases if they do not dress in this way at the very least they will draw the condemnation of their families and their neighbours.
They are forced to dress this way in order to escape such problems.