you can synthesize it, so you don't need it in your diet. only molecules that cannot be synthesized are required to be consumed via diet.
is totally backwards and wrong. that's treating your body as an endlessly powerful, infinitely capable machine with unlimited sources of energy - and that's crazy.
rather, the way this should be looked at is more like this:
you should only ask your body to synthesize molecules that can't be obtained freely from dietary sources; if you can absorb it, you evolved to do so, and consequently should.