> Ketchup really just means a fruit based sauce
No, it doesn't.
> so it long preceded the arrival of the tomato.
It did, but ketchups before tomato weren't necessarily fruit based. The original British version (and thus, the first American version, from which the other pre-tomato version derived) was mushroom based. Fruit, nut, egg, and bivalve-based versions all existed. (And the historical origin is in Asian fermented fish and soy sauces.)