You said (1)"our ancestors prayed for a thousand years and that deity comes first for any function in our family" (2)"All these diferences between Gods is a product of fundamentalism " Its not fundamentalism! Its your lack of knowledge! Your ancestors did correctly , as the Almighty GOD,takes shape or appearance, as the worshiper worships! You read"SRIMAD BHAGABADGITA", now available, translated, in many languages and read world over,and your knowledge will improve! Best wishes for you and wishing a speedy recovery of your correct knowledge!