In Jewish tradition people tear their clothes when a close relative dies. It is a sign of mourning called "kriah".
The Jews in Israel do it regardless of being religious Jews or atheists.
I saw this image on Facebook a few days after the October 7 Massacre, depicting a map of Israel as the torn part of the shirt.
I felt it as a very moving image showing how all of us, all of Israel is affected by the horrible death of the over 1,000 people.
Unfortunately, I don't know the source.