Birkot HaShachar: Why the negative approach?

The Birkot HaShachar, Morning Blessings, are rather infamous among feminists for the blessing recited by a man thanking HaShem for not having made him a woman and for the blessing recited by a woman thanking HaShem for having made her in accordance with HaShem's will. But that's not the only problem with those brachot/blessings. What about the ones thanking HaShem for not making one a non-Jew or a slave?

The Conservative siddur (prayer book) takes a more positive approach, with a person thanking HaShem for making her/him a Jew, a free person, and "in His image." Other siddurim and/or individuals substitute " . . . who has made me a woman" or "who has made me a man."

Why the negative approach in the traditional version of the Birkot HaShachar? Surely no individual can be held responsible for the way he/she was born. Yet the wording of these brachot edges uncomfortably close to casting aspersions, and I don't appreciate the traditional wording one bit. Apologetics miss the point--yes, a Jew, a free person, and a male have more opportunities and/or obligations to perform mitzvot/commandments, according to a more traditional approach to halachah/Jewish religious law, and the performance of mitzvot is considered a privilege for which to express gratitude, but one could make the same point in the positive.

This evening, we'll be ushering in the festival of Shavuot, on which we read Megillat Rut/the Book of Ruth, the story of a Jew by Choice. We might wish to give some thought to what we say about non-Jews.