Haaretz makes quite a few errors in its English, but at least the headlines should be done more carefully. "En masse" normally implies "all together" or everyone in one body, or the like. So, the headline here is quite misleading, as one finds when one reads the article. Please!
Man shot dead in northern Israel town of Bi'ina, police say the murder was gang related (Haaretz)
from the article: In Nahariya, some choose to leave, while others remain defiant