I'm not surprised that the rabbi was so straightforward about this issue. Interfaith marriages are especially bad for the Jewish community. There was an article on FR awhile back that analyzed the stats on marriages between Jews and Gentiles. Very few of the children of these marriages became practicing Jews as adults. It was something like less than 10% were practicing. Most of the children became non-religious.
Many children of interfaith marriages end up with no religion at all. Sometimes the interfaith marriage is the cause - the child is exposed to two contradictory religions and concludes that religion in general is just a pointless shame.
Other times the interfaith marriage is a result of a bigger problem. Namely parents who do not take their religion seriously. In my experience, if a kid's parents, whether they are Jewish, Catholic, or Protestant don't take their religion seriously, the kid will not be religious at all by the time he or she is an adult. If parents see religion as meaning we go to church or temple a few times a year, we put up nice decorations in December, or we just *are* a religion because our ancestors were and this should have no bearing on our behavior and beliefs, then children will rarely carry this weak faith into adulthood.
Adults who take their faith seriously do a better job of passing their faith on to their kids. But adults like this usually don't marry outside the faith. Usually they insist that their spouse be of the same faith. It's not that they hate other faiths or won't socialize with people of other faiths. But when it comes to the person you spend your life with and raise a family with, faith is usually a non-negotiable.
Meanwhile people who are nominal Catholics, Protestants, and Jews seem to be more likely to marry outside their faith. It doesn't bother them because they don't see religion as being terribly important. So we celebrate different holidays in December, so what? If religion is nothing but different customs then it shouldn't be so hard to combine and compromise. This kind of approach to religion is a sure-fire way to produce children who end up with no religion.
But this isn't an interfaith marriage problem alone. I can think of some nominal Catholics who have married nominal Jews and end up with children who are neither Catholic nor Jewish. But considering the attitudes towards religion that some of these Catholics already had, I can't imagine that if they had married another Catholic who was just as nominal, the children would have turned out any less secular.
People need to learn their faith, live their faith, and love their faith if they want to pass it on to their kids. Often people see an interfaith marriage as an obstacle to doing this. But if one doesn't have the right attitude towards religion, marrying someone of the same religious background will not do much to stop one's children from becoming secular.
Great post! You put it far more eloquently than I ever could.
It's worse than that. Almost no grandchildren of intermarried Jews are still Jews. The watered-down some of everything Chrismakah let-the-kids-decide strategy is a sham and hugely selfish. It makes the parents feel less guilty, but, statistically, it obviously is itself a decision. Making kids choose religion is worse than letting kids decide whether to go to school or play Nintendo. I have two intermarried siblings. One stepped aside and let the kids be raised as serious Catholics. The other is the typical tree/candles variety. As painful as intermarriage is to see when your people are demographically imploding, I much prefer to see the kids raised with serious commitment to God than to the bland secular nothingness (and liberalism) that is dooming the U.S. Jewish community far worse than anti-semitism ever could.