Here's some evidence for the side arguing that Jewish ethnocentrism is not significant.
I took the Jewish sample that was asked the question about the importance of one's ethnicity, and split it into two equal groups. The first group is people ages 18 to 54; the age range for the second is 55 and older. The mean "my ethnicity is not important" score for the younger group is 2.17 (n = 24); for the older group it's 1.83 (n = 24). That's three-tenths of a standard deviation drop in ethnocentrism among the younger group. The sample is small unfortunately, but combined with the high rates of intermarriage mentioned in the comments of the last post, ethnocentrism might be on the decline.
One other thing: even if Jewish American ethnocentrism were approaching Italian American levels among young people, Italians don't seem hypocritical to me. To put it mildly, they're not known for their crusading anti-racism.
UPDATE: Now that I think about it, the greater ethnocentrism among older Jews (that reaches levels similar to Mex-ams) might be explained as an age effect rather than a generational difference. People seem to discover their roots as they age.