Honestly -- and I before I say this, Free Palestine -- if you want to be a person who tears down a poster looking for a missing person, I think you should be prepared to live your life as a someone who everyone knows tears down posters of missing persons.
I think people have a right to privacy in the ways that don't affect other people, but when you do things that affect others -- whether that's not cleaning up after your dog or anonymously harassing whoever hung a poster of a loved one by tearing it down -- I don't feel you're exercising a right that I have some obligation to defend. Live with the reputation of who you are.
Again, I say this as a critic of the genocide in Gaza. Bibi Netanyahu deserves to be dragged into the Hague to face the International Criminal Court. At the same time, I still hope as many of the Israeli hostages are returned safely as possible, and I have no sympathy for people who are inclined to tear down a missing person poster and want anonymity. That's not liberating Palestine, that's just anonymously terrorizing whatever grieving person hung the poster when they discover it's been torn down.