Why couldn't Christians simply make a "Grandfather Clause" for Jews to continue their ways and for Christians to focus upon Heathens, Pagans, and Idol Worshippers, and to leave other Abrahamic Sects alone?
This IMHO shows a weakness in their theology that requires an intolerance for competition and a "My Way vs. The HIghway" thinking. Classic "I'm OK You're not OK" thinking, which is essentially hostile at its core.
Whereas Judaism only opposed Idol Worship etc. And never imposed Judaism on others, only the 7 Noahide Commandments. This seems a more balanced position of imposing minimalistic Abrahamide Monotheism without the need for rituals etc. Quite a balanced and mild approach I would say. What say you?
See also http://forward.com/opinion/327449/what-everyones-getting-wrong-about-that-vatican-memo-on-converting-jews/?attribution=home-hero-item-text-1