Yes, more efforts should be implemented to protect historical landmarks. Historical landmarks are very important because people can study these sites and learn from them. Allowing these important sites to be destroyed can lead to people forgetting an important part of history. More governments need to take more efforts to ensure that these landmarks are safe and secure.
The quote "those who learn not from history are doomed to repeat it" illustrates the importance of history in every day modern life. Since most of the destruction of these landmarks are caused by radical groups that are causing conflicts in the regions where these landmarks are, all efforts should be made to stop these groups and their destruction.
When trying to protect a population or land from attackers, the army can't destroy everything and start over, they need to be able to distinguish important landmarks of the societies they protect. As much as human lives are important, the landmarks serve to mark the past historical aspects of these people.
Any time a historical landmark is destroyed, we are outraged. If it is in our own country, we will do all we can to preserve something, if another country destroys their historical landmarks, we have no say in it, although we think we do. Our outrage becomes their goal and more monuments are destroyed. If they can't preserve them, we can't force them to and reacting to it just feeds their recruitment efforts.