We don’t know what might be taking place in the hearts of these Rabbis. Jews all over the planet have been realizing that Jesus fulfilled all the ancient Hebrew prophecies regarding Messiah, and trusting Him as their Savior. If these Rabbis are new believers, or near believers, it’s very shrewd of them to couch their appeal for a truce and cooperation as they did, and not drop the whole conversion bomb on their people all at once.
You are mistaken if you think that. Jews are responding to the changes in Christianity’s views on Judaism. This is a case of genuine friendship and respect but not of any acceptance of Christian doctrine. The messiah as understood in Judaism is very different from that understood in Christianity.