But in your sentence, ketchup is personified, which may be a nickname of a person or an anime character.
If it is simply translated according to ketchup, then it is'
Thanks for the ketchup.
It's a lovely statement, but it's not usually said that.
Generally speaking, I would say.
ケチャップをぃて, ぁりがとぅござぃま.
ケチャップをくれて、ありがとう。
If ketchup is personified,
And then translate it into,
Thank you for supporting ketchup.
There is no context and I don't know which one is correct.