I base my opinion on historical evidence. After Guru Gobind Singh's death, Sikh peasantry rose in arms under Banda Bahadur. Then Jats in the Sikh Misl [armed groups] fought all through the 18th century to establish Khalsa raj [rule]. Out of the 12 Sikh misls, 9 were headed by Jat chiefs. In this struggle, they made tremendous sacrifices. If one generation was wiped out, the next generation took up arms. Finally, they emerged victorious at the end of the century.

On his pro-Jat bias in his historical book. - Khushwant Singh: "Japji Sahib is Based on the Upanishads