In my grade school - 40 years ago - we sang christmas and hannuka songs, and "let there be peace on earth" - with a Jewish kid as soloist. If anybody had a problem with singing songs from another religious tradition, I never heard about it. I don't know what's happened in the intervening years.
It's called "respect". Most Christians (not all, but most) respect other religious traditions.
Indeed, the same could be said of courteous people adhering to any religious tradition. But, evidently, not Judy Maltz...
If this woman were a Christian, she'd be bitching about the Jews...