This is just as immoral as those who hate gay marriage or believe that interracial relationships are a sin.
No, it isn't. Religion is voluntary - a choice; sexual orientation is not.
You are oppressing an entire group of people and you just don't give a shit, using the pathetic excuse of "well, our culture is just like that" to defend it.
On the other hand, the argument against what you term oppression is "well, their culture is just like that". It is entirely reasonable to reject those tenets of a culture which are based in and propagate discrimination. One of the fundamental principles of the French Republic is equality; the cultural elements that drive the wearing of a full veil undermine that principle; without those oppressive elements, I am certain we would not be seeing the present reaction to veils in France.
It is equally reasonable for a people to decide what parts of life are and are not proper in the public square. The people of France have chosen to exclude religion from that square - no less than the people of America have chosen to exclude nudity from it. It remains within the rights of all French persons to practice their religions in privacy.
This is the exact same reason women aren't allowed to go topless on most US beaches.
Are you in favor of mandatory topless beaches? (And not optional, mind you. Mandatory. You MUST go topless to visit any beach.)
The beach clothing issue is somewhat more complicated: First, the lower portions of male swimming outfits are generally less revealing than are those of female swimming clothes. Second, many males wear tops (generally t-shirts or tank tops) on the beach; females are more likely to wear tops, but are also often not permitted to go without them.* Third, unless I'm mistaken, female swimming tops often provide support or confinement, which can increase comfort - a practical purpose, not based in discrimination.
* As a person who values equality, I find this objectionable.
What's that seriously ? 
