The Jewish leader's influence on their followers has nothing to do with modern technology or the lack of it but rather has to do with the leaders themselves. Those who are true Jewish leaders (the article describes it as having self evident moral authority) have nothing to fear from modern technology. On the contrary we see leaders such as the Lubavitcher Rebbe encouraged the use of modern technology to its fullest and yet his respect and authority was and is absolute among Chabad. His authority did not come with any power of enforcement but rather from who he was as a person. When there is a true Jewish leader then the whole world, non Jews as well as Jews respects him.
Militants loyal to Islamic State claim suicide bombings in Nigerian capital (Reuters)
from the article: The ultra-Orthodox arrived en masse