According to you Pad Thai and Tom Yum Koong are not Thai, Sushi is not Japanese, Spaguetti is not Italian because the noodle and rice were not originally from those countries and the fish, tomatoes, and spices were imported from somewhere else.
You are so desperate that you now try to manipulate the truth.
Who cares what Thai call this or That, the point is Tum Mak Houng and Larb are Lao national dishes. They were NOT known by Siamese before. Tum Mak Houng and Larb were dishes for Lao people in the east and west banks of the Mekong before Esan was conquered and incorporated into Siam. It was through the Lao Esan people that Tum Mak Houng and Larb became popular to central Thai people who now call it Som Tum and Laap. Now Thai try to promote them as Thai dishes to westerners. Now you want the world to know they are Thai dish. NO, Tum Mak Houng or Som Tum and Larb are Lao national dishes, that become popular in Thailand and even in Cambodia. Even many honest Thai never consider it to be Thai, it's Lao dish.