Especially WWI, the Brits complained that the U-Boats were sinking their ships, while Britain was enforcing a Naval blockade on Germany. It was much easier to cut-off Germany from ships than Britain, the U-Boats were just trying to level the playing field.
And the fact is, if the US was truly neutral, they would have told the Brits they wouldn’t get anything from us, unless they ended their blockade of Germany.
There’s a reason why the sunk Lusitania has been offlimits to divers for 103 years - the UK Government doesn’t want them finding the war explosives that it illegally carried and which made it a legitimate target for the German U-Boats under the international rules of war in World War One. The Lusitania was bait, the Brits knew there would be an outcry in the US over the unprovoked murder of US citizens; they were quite content to lose them and a thousand Brits in order to spur support for US entry into a literally crazy war. I have no brief for the German government in WW1, but it wasn’t marginally worse than those of our European allies.