I don't like the way this thread has turned out.
Jews are against missionizing for very good reasons. In the past, suggestions to Jews to "save their souls" were usually followed by brute force if Jews wanted to stay Jewish. The same thing can also be said of other non-Christian groups who came in contact with explorers and their missionary minions. In today's more politically correct age, missionaries stick with deception, head games, and/or stalking.
Now the purpose of Israel is to be a Jewish ethnostate for Jews where they can freely practice and live according to Judaism. The Bible predicted that Jews would one day return to their land, and it has come true. It is ONE tiny pipsqueak country in a world where there are dozens of Christian and Muslim countries. There are billions of Muslims and Christians in this world. Unfortunately, the same can't be said of Jews. And to sum it up, whenever a Jew dies, or if he leaves the Jewish religion, that's still one less Jew in the world. So of course JTF will vehemently oppose anyone who tries to get Jews to abandon Judaism, even more so when it's one of our own.
Regarding Ron Ben Michael and Muman's posts, I just want to make something clear. According to Judaism, when Messiah comes, people will all want to know and worship G-d. In such a scenario, they'll either become Jewish or Noahides. Christians, from what I understand, believe that Jesus will come a second time, at which point everyone will become Christians.