Change and development/growth are different things.
Take for example an orange seed. The seed germinates and there is a plant ... so does the orange seed change its reality?... NO ... it just grows ... and then oneday a tree comes ... and its gives fruit! IS THAT FRUIT A MANGO?... No ... its Orange. That is nature.... Although the seed turned into a tree ... but it did not alter its basic reality ... it grew stronger and more fuller ... more meaningful.
In the same way ... the cultures are to grow ... and so will morality. Just like through the Roman Empire or the Harems of the Sultanats ... we have grown out into a more civilised way when it comes to man and woman relationships ... marriages ... etc (Read: Fall of th Roman Empire - GIBBON, its described there very nicely).
Why husband wife kissing offends people? ... Well if its in public, it does. Because its carnal in nature, and others are not. And this is a code of conduct ... something we have developed (and YES ... accepted)... and this you may not like - but many do ... and surely will. Because, as I said before ... atleast I personally have deep faith in this development of a better civilisation with greater promotion of modesty, moderation and kindly behavior. YOU MAY NOT AGREE - I said before - I am not here to change anyones view or force mine.
@RTH:
Regarding the lady testing her LEGAL RIGHT. I have nothing to say but ... it also proves that anything which is not a noted crime, is not necessarily an acceptable/respectable behavior.
There is no harm to be respectable or moderate ... people can still satisfy their carnal desires (personal opinion would be, as properly and responsibly as possible).