In a nutshell, the Left would like everyone to have no identity, or at least, that everyone's identity should be reduced to the lowest common denominator.
Gender: Those on the Left believe that there is no such thing as an innate gender, (except when it comes to gays who they feel were born that way). They think that boys and girls are the same, men and women are the same. The only differences between males and females are imposed on them by a paternalistic, oppressive, archaic, class of men. The Left would like to see everyone cast off the shackles of their sexual identity and live as sexless creatures, where boys are free to play with dolls and dress in girls' clothes. There should not be husbands and wives, there should only be "partners". Heterosexuality is also an oppressive construction. Married couples are seen by the Left as a continuation of an oppressive system. Married women, no matter how happy they are, are contemptible fools. And the worst thing a married woman can do, according to the Left, is have children and stay at home to raise them. Hillary Clinton said it best, when she condemned women who "stayed at home and baked cookies".
Ethnicity: According to the Left, if you are white then at the very least you are the beneficiary of the white ruling class. Maybe you weren't a slave owner, but you can't deny that you have benifitted from a system that has continually oppressed minorities. According to the Left, if you are white, you must atone for the sins of your forefathers. Certainly you may not make a claim to a good job or a spot in the universities based on your own merits. If you succeed as a white person, you must have cheated or oppressed someone from a less priveleged ethnic group. Charity to less priveleged groups won't win you an ounce of forgiveness either. The only thing you can do as a white person to redeam yourself is fail. Becoming an outspoken advocate for affirmative action might help you also. But you can't hide your colour like you can hide your sexuality. So if you happen to have white skin, you'd better be actively ashamed of it.
Religion: The worst thing you can be, according to the Left, is Jewish. A distant second is Christian. If you happen to be Jewish or Christian, the Left would have you either convert or actively advocate against your religion. Michael Lerner is a great example of a Jew that the Left can tolerate. The Left doesn't love him, though I'm sure he thinks they do, because he is after all a Jew. But this kind of Jew they can live with because he is trying to destroy the Jewish people. So they will thinly veil their contempt for him. As for Leftist Jew hatred in general, it is incurable. They want Israel destroyed and they want all of the Jews destroyed (G-d forbid). Unlike most of the muslims, the Left would never admit this openly. Leftist hatred for Christians has more to do with the perceived oppressiveness of Christianity than with a pathological desire to destroy Christians. The Left says if you are a Christian, keep it to yourself. No Christmas trees, no Christian religious symbols, no nativity scenes, no Biblical references, no Christian prayers in schools (muslim prayers are fine), certainly no Christian advocacy for Israel. The Left would prefer that life were meaningless, so they would have permission to act as badly as they want to. G-d is a stumbling block for the Left. All of that morality is really oppressive. That's why they don't have a problem with islam--because islam is predicated on a doctrine of evil. Any moral standard is a wall that has to come down. This is why it does not matter to Leftist feminists that women are treated like beasts in islam. The important thing is to the Left that islam gives permission to the worst sort of behaviour. The Left needs islam in order to feel better about their own immorality.
Class: The Left's doctrine is based in Marxism. Any success is the result of having cheated someone. Any failure is the result of external oppression. Government is needed to enforce equality. The Left favours equality over freedom. That is why the Left favours captial gains tax increases. Even though it would reduce revenue (which has been proven by the way), it increases equality. Tax increases bring everyone down to a lower level, except the lowest level. There is no such thing as earning success or for that matter earning failure. Class structures are the result of oppression.
The bottom line: The Left wants everyone to be the same, so they say that everyone is the same. People are morally equal, whether you are a successful businessman or a suicide bomber. The world they are trying to create will have no class structure, only a working proletariat class. There would be no religions, save perhaps only those religions that allow evil and call it good. (I can only think of one religion in this category). There should be no genders. People should be able to have sex with whatever they want to. Saying otherwise is oppressive. Men would be like women. Women would be like men. There would be no moral standards, no personal identities. Culture should make no statements. Everything should be reduced to dregs. And all that should remain of the world as we now know it is a museum somewhere featuring exhibits of a less enlightened time.