Why were the British attacking our ships?

During the war between the French and the British, the United States decided to stay neutral, and like with most wars, they needed supplies. The United States decided to take the opportunity to benefit off of the war, and their neutrality, by trading with both sides. Both the French and the British realized that the U.S ships were bringing supplies that would better their opponents chances of winning the war. Soon the British were taking U.S ships bound for the French, and France intercepting U.S ships bound for the British. But the British not only took over the ships and it's supplies, they also used the ship and it's crew and forced them into their Navy, where they were forced to remain and endure the hardships of life at sea and a war enforced upon them.