Why must women pray behind men? Why is it that in Pakistan women have the worst place to pray when we need to pray in public and/or in the masjid? And also, why must men and women be separate in public? Isn't that inconvenient? What is the wisdom behind all of this?
The wisdom in women praying behind men, which is the same as the wisdom in women wearing non-revealing clothes, is to take sexuality out of public interactions, so that people can get on with their lives and do what needs to be done without male-female sexual dynamics becoming a factor.
Men are designed to find women far more physically interesting than women are designed to find men. What this means is that having the women in front of the men at the mosque will cause more distraction, on the whole, than having the men in front of the women. Since the goal is to focus on God at the mosque, the logical thing to do is to not have the women in men’s sight. Since women do not find men particularly physically interesting, in general it doesn’t do any harm to have the men within the women’s sight.
Some will say it is men’s duty not to look at women lustfully, women shouldn’t have to dress a certain way or sit in a certain place just so that men wouldn’t be distracted by them. Islam deals with the issue on both ends, it asks both sexes not to look at one another lustfully, and it asks women to dress modestly so that if men do look, they do not see much to look at
At the mosque, it adds an extra degree of conscientiousness to have the women pray behind the men, to make lustful glances even less likely, so that proper respect for God is shown at His house.
We are all God’s servants and it behooves us to organize our public spaces in the way that is most likely to please Him. If having the women pray behind the men is more conducive to proper respect for God, and less distracting on the whole, than having the men pray behind the women, then it logically follows that it is best for the women to pray behind the men. The goal is not some power play or show of authority by the men, the goal is to show God proper respect, with both sexes being His lowly servants wanting to please Him.
As for why men and women can’t pray mixed like at church services, it is again because it adds an unnecessary gender dynamic to the act of praying at the mosque, which is unnecessary and not something God wants to be present in His house. Most of us are capable of praying alongside the opposite sex without any issue. But it is better not to mix, and since we want to please God, we do what is better. Amish Christians do the same, with the men and women sitting separately at church.
About separation in other public places, the point again is for public interactions to be civilized and free from lust. Islam has no issue with men and women interacting in public, it only wants to give the best shape to these interactions by removing potentially harmful dynamics. Each Islamic culture has its own way of trying to achieve this. Some cultures take the separation of men and women too far, and others have sensible policies that do not lead to inconvenience. Much of it is cultural tradition, there are no rules regarding separation of men and women in public in the Quran, for example.
I am sorry to hear that women do not have good places to pray in public in Pakistan. This could be a carryover from the past, where women venturing outside was far less common than now, so that there wasn’t much demand for better accommodations for women. Hopefully this will get better with time. In the United Arab Emirates, for example, the malls have large and well-maintained spaces for women to pray.