This seems to be more true of mutually exclusive religions that are historically geographically close together for an extended period of time than ones which happen merely to be doctrinally similar, and to be more (but certainly not exclusively) true of political conflicts between religious communities rather than theological conflicts.
> But, for now at least, we have lots of Indians (Sikhs and Hindus) here in the US and don't have the problems with them that we do with others
Part of that is because the people who would have problems are still mistaking South Asians with Middle Easterners and also (whether or not they do that) assuming they are Muslim. Give it some time, they’ll get their own targeted hate. (Hinduism already gets some through the Christian anti-yoga movement.)
Of course, part of this could just be physical proximity: these warring groups tend to be neighbors or even in the same places, causing friction. But, for now at least, we have lots of Indians (Sikhs and Hindus) here in the US and don't have the problems with them that we do with others.