Of course it should be an option to want to place a kid in a Christian home. It's disingenuous to say that this is about Jewish parents in particular, when the same interest would apply to any non-Christian home. It doesn't matter if it's a Jewish, Muslim, Buddhist, or secular home.
The question is whether the government should be funding agencies who discriminate on the basis of religion. I’m sure some Americans feel as you do, but it raises some constitutional issues.
A challenge is that the free exercise of some religions (such as evangelical Christianity) requires evangelism of those who don't share that religion. If you believe that every non-Christian is going to Hell, then intentionally putting a child in an environment where he or she would not be raised Christian is risking eternal damnation for that child. I'd argue that doing this is part of the free exercise of religion for the adoption organization.
However, this is clearly discriminatory against non-Christian adoptive parents. It's functionally equivalent to putting up a sign on the door to a restaurant or hardware store saying "we serve Christians only." You might argue that the right to discriminate against people of other religions is an inherent part of freedom of one's own religion, but I believe that argument would not hold up in court.
