[svmzextd] Hate groups and intermarriage

Hypothesis: hate groups form against groups which are internally effective at preventing intermarriage between their members and the rest of society.

Counterexample: There seem to be very few if any hate groups against the Amish. (Update: friends from Ohio and Pennsylvania report that xenophobic hate against the Amish does exist locally there.)

Modification of hypothesis: Hypothesis only holds in a nonsegregated society: they are forced to interact often.

Ironic in that the hate groups themselves often advocate the prevention of intermarriage.  This suggests the actual mechanism which causes the hate is complicated.

If the hypothesis is true, hatred towards homosexuals will never cease, by tautology.  It also suggests that such hatred should be universally present everywhere and at all times in history, a dubious prediction.

Perhaps it does not hold in societies with primarily arranged marriages?  If so, why not?