Why did the Germans believe that the bombing of the Lusitania was justified? Why were the British outraged by this event?

Germans attacked Lusitania because they knew the British used it to transport weapons and supplies from the United States. That caused the outrage of the British, because Germans broke the naval rules and killed approximately 1200 people. The attack occurred in 1915.

At that time, Lusitania was the biggest and fastest ship in the world. In 1915, Germany declared the area around the British Isles a war zone, warning that all the allied ships would be sunk without any previous announce. However, Lusitania continued with a regular sailing, so German submarine sunk the ship, which caused many accusations against Germany and was the main reason for the U. S. to enter into the war.