Complex sentence: Israel defended those checkpoints as being necessary to stop militants and limit the ability to move weapons around, while Palestinians and Israeli and International observers and organizations perceived the checkpoints as excessive, humiliating, and a major cause of the humanitarian situation in the Occupied Territories.
Split into simpler sentences: Israel defended those checkpoints as being necessary to stop militants and limit the ability to move weapons around. However some Palestinian, Israeli and International observers and organizations have criticized the checkpoints as excessive, humiliating, and a major cause of the humanitarian situation in the Occupied Territories.