From Rabbi David Wolpe:
Rabbi Shlomo Carelbach used to say that if he met a person who said "I'm a Catholic" he knew he was a Catholic. If he met a person who said "I'm a Protestant" he knew he was a Protestant. If he met a person who said "I'm a human being" he knew he was a Jew.
Jews have led some of the great universalist movements of the world. They did so under the illusion that if all people were just alike, the thorny problem of being different would disappear. It never did. It never should. Being a Jew is not a problem but a blessing and a destiny.
There is no such thing as a person in general. Each individual grows up with a certain family, land, heritage, language and culture. To deny it is to cast off a piece of oneself. Jewish is not opposed to being human; rather it is an ancient and beautiful way to be human.
In every age there are those who dream of homogenizing the world. It is an ignoble dream. When we honor difference we honor the One who created this diverse, multicolored pageant of a world.