Cornish and Welsh wore kilts.

[Graywolf]

Alright, so as I understand it, the kilt as we think of it today is of Scottish origin, developed after the price of wool became affordable. However it descended from the Irish liene and a pleated Viking garment, from which the word "kilt", meaning pleated originated. So we have Scottish, Irish, and Scandinavian. Finally, if I am not mistaken the oldest plaid garment was found in a tomb of red-haired, Caucasian people in western China. This tells me everyone has the right to wear a kilt.

[Chef]

However it descended from the Irish liene

No it's not. he fact that the liene was worn in both Scotland and Ireland does not mean the kilt is descended from it.

and a pleated Viking garment

There are many pleated garments around the world that have nothing to do with the Scottish kilt. The link to any Viking Garment is dubious based on the length of time between the Viking influence and the emergence of the kilt.

from which the word "kilt", meaning pleated originated.

Kilt is an English word of Scandinavian origin (as are many others) meaning "tucked in", but that itself shows no Scandinavian origin of the kilt in Scotland.

Finally, if I am not mistaken the oldest plaid garment was found in a tomb of red-haired, Caucasian people in western China.

Patterned woven materials show up all over the world, it's a function of weaving, but again o direct link to the Scottish kilt.

This tells me everyone has the right to wear a kilt.

I never said otherwise. Choose to wear the kilt because you like it or for any new meaning you want it to symbolise, just don't make up an historical justification for it.