You are missing the point. They let users delete history but only allow users to remove items one by one. If going to let users delete items why not allow them

You are missing the point. They let users delete history but only allow users to remove items one by one. If going to let users delete items why not allow them to remove all at once? The only reason I can think of is that they know people will get frustrated removing each item one by one... so they quit.