Why is Greece known for their Greek gods?

It's because the relationship of the Romans and Greeks, in that the Roman civilization ruled much of Europe for a very long time and applied the worship of their gods and goddesses: Jupiter, Juno, Pluto, likened them to the Greek Zeus, Hera, and Hades. As the Romans expanded their Empire, they also "adopted" the conquered peoples gods/goddesses into their own and showed those foreign gods/goddesses as aspects of other gods/goddesses.