Hinduism was undergoing agitated and problematic times after the formation of Islam and Muslim religion. Hindus were coercively being converted to Islam. Islam being a monotheistic faith clashed with Hindus due to their following of different and multiple gods.
Furthermore, the Mughal emperors of that era were not respecting Hindus and their beliefs.This brought about a need to save Hinduism from extinction and relentless conversions. Sikh Gurus, with origins in Hindu families, formed a fearsome force of ‘Khalsa Sikhs’ to oppose this tyranny and oppression and help hindus return to their polytheistic religion.
The lend lease act provided aid to any country who needed it, thus when WWII began they were trusted and were ailed forces together(also Roosevelt lended Britain arms)