If you look at the article at the link, there is a picture of some writing on the side of the mosque which was attacked, and the caption says that the writing is Hebrew for “price tag.” The context of the article would imply that, when a group of Israelis takes revenge for some violent act on the part of the Palestinians, they leave the words “price tag” to explain why they did it. It’s the price the Palestinians pay for their violent acts.
The Jews were taking “revenge” for the actions of the Israeli police.