You are refering to the Krebbs cycle, which is a metabolic pathway, like many, existing in currently living things. These metabolisms are the products of evolution, not biogenesis. Yes, organic materials can be the products of living things. Such organic compounds can be synthesized in the lab, too. That is a really big study - the synthesis of natural products without the use of living things. However, biogenesis requires the exploitation of naturally occurring organics. Invoking a currently existing metabolic pathway presumes such a pathway was the product of biogenesis. That is not necessarily the case and indicates, as you have mentioned, that certain organics found in the complicated metabolic paths of even simple cellular organisms present today could not have existed during biogenesis. This is also a clear indication that whatever the first life forms were, they are not comparable to today's cellular life forms.
Since it is the pathway used in even the simplest of cells as far back as we can ascertain, it is a conclusion warranted on the evidence.
That is not necessarily the case and indicates, as you have mentioned, that certain organics found in the complicated metabolic paths of even simple cellular organisms present today could not have existed during biogenesis. This is also a clear indication that whatever the first life forms were, they are not comparable to today's cellular life forms.
This is a circular argument: Abiogeneis didn't create cellular metaoblism because cellular metabolism cannot be formed by abiogenesis. You're caught in the circle because you are treating the premise as fact. That's a no-no.