To be fair it's weird in the USA where you might have states were open or concealed carry is completely legal but things like swords or knuckle-dusters are a crime to carry in public.
Yeah I believe they were all banned related to various racial and national groups. Like knuckle dusters initially for Italians and now a perception around Black people. Nun chucks etc for the various Asian diasporas.
Yeah, all the kung-fu movie weapons - nunchucks, ninja stars, butterfly knives, were banned in the 80s because boomers saw some action movies and were like "woah a new way for me to be racist!"
I think a lot of them because most cannon are smooth bore and black powder which in many state aren't even considered a firearm. So yeah you could have a swivel gun from a ship under your trench coat.
Legality of arms in the us is basically just "how white coded is this weapon?" The more strongly weapons are associated with minorities the less legal they are.