No, no, no! To force religions to unite is to deny human rights. Freedom of religion and conscience is nothing if one's religion is forcibly melded with another. Religions have every right to have as exclusive and non-left-wing belief systems as they want, so long as others in society are not physically harmed. And a one-off ecumenical event is no excuse for permanent use of worship places by different faiths.
I agree. "Real" Jews don't want to be a part of "One World Religion" any more than "Real" Christians do.