While I am not Homophobic, or Homosexual, I have a couple of gay/bi friends - And I don;t have much of an opinion on it. However, regardless of my feeling about homosexuality, I see Homophobia as a much worse offense regardless of cultural background or opinions.
But, Like you I would still be surprised at seeing it in a "normal" club. Simpley because not everyone shares my opinions. their are alot of sick people, who place much emphasis on sexual oriantation, as if it was the most important thing in the world. There are places in parts of the world where it is considered a capital crime!
I would not be shocked or disgusted at the kissing itself, but I would still be surprised that it took place so openly, in a sociatey which so often looks down on people like them - and also quite pleased that they were allowed to openly express their relationship without fear of persecution. It would be considered unusual in my opinion, only for that purpose.
I think what your are trying to say, is that it seemed odd there was no reaction from the people around them? I don't know where you live, but it sounds like it must be a pleasently more tolerant place then alot of the world.