Well, 'similar' and 'dissimilar' are elastic concepts, and as the pantheons mentioned are certainly not 'the same' there is much room for interpretation, where different schools tend to stress the difference more than the similarity or vice versa. But there are sufficient common characteristics to trace a lineage in all of them, albeit certainly intermixed with other influences.
In the specific case of the Greek mythology, these deities have distinct Indo-European parallels: Zeus (Dyēus, Sky Father), Eos (H₂éusōs, Dawn goddess), Helios (Seh₂ul, Sun god), Castor and Pollux ( Divine Horse Twins), and more, enough to at least put central tenets of Greek pantheon largely within the realm of the Indo-European tradition.
The cited quote in isolation gives an incorrect impression in this context.