Maybe they should be illegal?

Marmelades can't be made from carrots in the EU, we have the Brits to thank for that who insisted that the term is restricted to citrus fruit, the rest is jam. Especially nuts because the term derives from Portuguese "marmelada", quince mush, and quinces are definitely not citrus fruit.

Speaking of the Portuguese yes they gave us that classification of carrots as fruits so they didn't have to call their stuff "carrot spread" or something. Noone else on the continent cares, it doesn't have any impact on anything else, and next time definitions are re-done they might just leave out the "has to be fruit" part in the definition of jam, or "fruits, or vegetables traditionally used for jam, or with sufficient fruit-like character".

I guess some lines have to be drawn though otherwise Nutella is going to start calling itself hazelnut jam.