That’s the propaganda line. The Lusitania was an ocean liner of the Cunard Line, not a supply vessel. 128 American deaths went unavenged for two years, and to accuse them of somehow “violating neutrality” is a direct insult to them and their descendants.
An alliance with the Second Reich would have violated what the US stood for. If not for that Reich inciting Mexico, Wilson may have considered just that.
Why then was the ship carrying munitions?
Do you deny that it was shipping weapons to Britain? Do you deny that the German embassy warned passengers in advance of this fact?