Some people avoid labels, but not me. I'm a Jew, a humanist, a secular humanist, an atheist, an agnostic, a skeptic, a freethinker, a rationalist, an infidel, and much more. Which label(s) I lead with depends on the context and with whom I'm communicating, but they all help define me in some way.
According to all branches of Judaism, I'm Jewish because my mother was a Jew. I accept this criterion. I've met quite a few atheists with Jewish mothers who have tried to convince me that I'm not Jewish because they (the atheists, not their mothers) reject the traditional definition and assert that a real Jew must believe in God. These atheists are free to declare themselves not Jewish, but they have no right to tell me that I'm not.
I grew up in an era that saw considerable discrimination against Jews. In the 1950s it was not uncommon for Jews to change their names and try to pass for gentiles, hoping for acceptance into mainstream culture. I found this deplorable. My Jewish juices flowed most deeply and proudly when anti-Semitism was present. Having relatives who died in the Holocaust, I was not about to give Adolf Hitler a posthumous victory by killing off my own Judaism.
But my Judaism is more than anti-anti-Semitism. I'm a cultural Jew in many ways. I like latkes, knishes, and even gefilte fish--which makes me a gastronomic Jew. There are other aspects of Jewish culture and values that have shaped me as well. A disproportionately high percentage of Jews have been engaged in civil rights activism, for example, and it's also a certain point of pride that while numbering less than 1 percent of the world population they have earned 21 percent of Nobel Prizes. And probably most Jews belong to a branch I call "humoristic Judaism."
Here's my favorite Jewish atheist joke: When a Jewish atheist heard that the best school in town happened to be Catholic, he enrolled his son. Things were going very well until one day the boy came home and said he had just learned all about the Father, the Son, and the Holy Ghost. The father, barely able to control his rage, seized his son by the shoulders and said, "David, this is very important, so listen carefully: there is only ONE God--and we don't believe in Him!"
I prefer the label "Jewish atheist" to "Jewish humanist," though I think the two labels mean pretty much the same thing. You can be an atheist without being a humanist, and you can be a Jew without being a humanist, but those of us who label ourselves...