... they certainly looked like they were having a great time ...
this may be a stupid question, but where there any women at that wedding? ...
Yes, and if you think the men were having a great time, the women almost lifted the roof of the building.
The hall is split in two you can kind of see the "mechitza" (separation) in the video.
The reason is that in Orthodox circles a woman will not dance before a man who is not her husband. Men and women will not touch a person of the opposite sex who is not a spouse or close relative.
I could give a whole explanation of the reasons but not sure that religious discussion is welcome here. Suffice to say that although the separation is one of the most misunderstood customs of the Orthodox community and opens us to lots of (false) accusations of sexism, it happens to be a beautiful and meaningful thing, not to mention the resulting lack of infidelity, jealousy, divorce, etc., etc.