Heh heh, Americans will finish posting their “British food” memes and then go back to squirting flavourless yellow paste onto a bag of par-boiled ground pigdick.
Naming them by the country of origin is almost equally odd to me. You literally mentioned Dijon, which is also French. So wtf is French mustard supposed to mean. There's probably dozens or hundreds of French mustards.
To make it worse the UK has a weird "French" mustard which has nothing to do with France, its this darker, sweeter, less spicy mustard that Colman's invented and no longer make but you can still find own brand ones in the supermarket. Actual French mustards are referred to by name.