Mycenaean's were Greek. Same as the Macedonians, the Athenians, the Spartans, the Corinthians, etc.

Americans? I think they mean Texans.

Hm, it is a bit like calling Leif Ericsson an American. Somewhat truish, but the time gap between him and the actual early US is really huge, approximately as big as the gap between the Mycenaean Bronze Age and Early Classical Greece. Lots of development in between.