Why is it ok in this country UK ok to call a German a kraut or a french man a frog or a scottish man a scot in the national papers but not ok to call a Pakistani man a paki?

Answer 1

Although you write that it's okay to use names like those for people, you probably aren't using those terms when you speak to those people in person.

A basic human skill is respect, and when using terms such as those you've used, you deny yourself your own ability to show respect, by disrespecting whole nations full of people.