"There are Sikhs who claim they should be able to bring knives to school."

No child is allowed to bring a knife to school, ceremonial or otherwise. I've never heard this argument. Can you cite a reference?

"There are Middle-Easterners who claim the should go forward with marriages between 40 year old men and 13 year old girls because it had been arranged by some previous agreement."

Again, please cite the source of this.

"And there are Mexicans who are illegally in the country who think they should be given drivers licenses."

I haven't really followed this controversy. What does citizenship have to do with the ability to pass a driver's test? Is there a law that says only U.S. citizens can apply for a driver's license? Seems to me there are alot of non-citizens driving in the U.S.