I read elsewhere...
Fundamentalism is akin to orthodoxy that is intrinsically prejudicial, parochial, dogmatic and adamantly averse to any changes social, scientific or religious. Driven by orthodoxy the Hindu neo-nationalism drove Buddhism out of India and stunted Jainism's growth. Christian Powers embarked upon crusades under papal sanctions against Muslims in 11th, 12th and 13th centuries. The Muslims have been waging recurrent jihads ever since the inception of Islam. Many polygamous male dominated Muslim theocratic states have been enforcing Islamic code in which men can have four wives and women are denied education and career opportunities. The medieval Roman Catholic judicial system conducted inquisitions for discovery, examination and punishment of individuals and political groups with total disregard for the individual rights, for the ultimate purpose of enforcing orthodoxy.
Ironically a fringe element of Sikhs tends to treat the noble concept of Khalsa Panth like such fundamentalism, which in today's vocabulary is synonymous with militancy, fanaticism, radicalism even terrorism.