"White's Gentlemen's Club in London has been going strong since 1693 and still doesn't admit women. There's plenty more in the UK. Is that okay in your opinion, fender?"
If you must make such an inappropriate comparison you should note that whilst women are excluded from places such as White's Club (as permitted under Equality legislation) it does not cause women generally any great harm (in fact, as with membership of the Freemasons, many women may consider it a positive advantage not to be permitted membership).
By contrast, women living in traditional Muslim communities are very much second class citizens. They are expected to be subservient to their husbands; their association with men is tightly controlled; the way they are allowed dress is under a strict code; their inheritance rights are curtailed because of their gender; female offspring are less valued than males; education for girls is seen as unnecessary; in some strict Muslim countries they are not allowed to drive; under Muslim law men are allowed up to four wives (women are allowed just the one husband). To give you a flavour of the philosophy and beliefs that lead to this treatment, here's a few ideas from the Hadith (the teachings of Mohammed):
Bukhari (6:301) - "[Muhammad] said, 'Is not the evidence of two women equal to the witness of one man?' They replied in the affirmative. He said, 'This is the deficiency in her intelligence.'"
Bukhari (6:301) - continued - "[Muhammad said] 'Isn't it true that a woman can neither pray nor fast during her menses?' The women replied in the affirmative. He said, 'This is the deficiency in her religion.'" Allah has made women deficient in the practice of their religion as well, by giving them menstrual cycles.
Bukhari (2:29) - Women comprise the majority of Hell's occupants. This is important because the only women in heaven ever mentioned by Muhammad are the virgins who serve the sexual desires of men. (A weak Hadith, Kanz al-`ummal, 22:10, even suggests that 99% of women go to Hell).
Do you really seek to compare treatment such as this with not being allowed membership of White's club? Your comparison is specious. In fact it's more than that it's just plain silly. You might as well ask why men are not allowed to join the Women's Institute.