I put "first you have to eat soup" and got the answer that it had to be "the" soup, and I don't think that's true, one could be speaking generally.
I'm sorry, but this translation is not correct. In English you don't "eat" soup, nor "drink" soup, but "have" soup.
The DL answer is "First you have to eat your soup" so maybe you want to change it?
and of course there is no YOUR in the czech sentence - nothing in the sentence indicates you have to eat YOUR soup, just SOME soup
I agree, that's the problem with lack of context. If it's a parent telling a child they have to eat their soup first before they get the main course, then they would use 'your' or 'the'. However, if it's someone talking about the general conventions for order of courses in a typical Czech lunch, then it would be soup in general.
As a native speaker of British English, I would eat soup with a spoon, or drink it from a cup or a flask. So I have no problem with the translation.
If you don't eat your meat, you can't have any pudding! How can you have any pudding if you don't eat your meat?!
When translated to Czech, the your will be skipped. Jestli nesníš maso, nemůžeš mít (žádný) dezert! Jak bys mohl mít dezert když nejíš maso?