True.  And, generally all of those people (except Jews) shared a common religion, Christianity, and as a result, similar shared morals and values.  (And even as between Christians and Jews there are significant shared values).  The acceptance of woman in society during the 20th C is a great example.   For sure, these shared values helped with integration.  To a large extent, the same isn't true with Muslims and I think we're seeing a clash of values, and I'm not sure that it will ever be fully reconciled...in many ways, this is uncharted territory.  Views and tolerance of woman, homosexuality, shame, freedom, to name a few, all require a great evolution in thought.