[srean]

They are closer to the "An Irishman and a Scotsman …" genre. Part of the reason there are so many Sardar jokes (that's what they are called) is that they (the Sardars) are very sporting and secure people. They don't mind being a butt of these jokes and start many of those themselves. My roommate (who was a Sardar, equivalently, a Sikh) used to say he would keep two glasses, one filled with water and another empty, in the night on his bedstead because in the middle of the night he might be thirsty, but then he might not be. Things like these are essentially baits to encourage such jokes.

But back to the PP a big part of Sikhism's break from Hinduism was the rejection of casteism. So it is built in. Someone who is more familiar will be able to elaborate more. What I have heard is that its root lies in agrarian anti-caste movements.