The Princess joke at the end of Kingsman (2015)

A princess offers our hero anal sex, if he saves the world. All this in a film that is very conscious of just what it is doing, and well aware of the kind of film that it is. "This is not that kinda movie, bruv", we are reminded, yet people take offence to this joke. Why so? Discuss the impact of such dialogues or why their existence shouldn’t be questioned, if not justified.