Maciamo,you make good point that J2 could have come in Southern Europe 1200 B.C around the time of the sea peoples,if we asume that during this time was really a migration or as you explained the subjected could have took arms against their overlords,it seems that there were two migrations in what is today Greece or Southern Europe and probably spread more north?if we even take the Greek mythology and myth,their claim of ancestry on Danaus(Daanans or Achaeans) that were part of the Mycenaean Greece they trace their ancestry in Egypt with some myths further to Hyksos people,which were expelled around 1580 to 1550 BC reign of Ahmose in Egypt,Mycenaean civilization is asumed to have lasted from 1600–1100 BCE the years match,Hyksos origin is difficult to explain but they were prevalent Semitic ancestry with maybe some Hurrian but Indo-European component is difficult to explain,however this go against Indo-European language hypothesis in Greece and the previous inhabitants,Semitic component in Minoans is easier to explain their language is not Indo-European either,but can they spread this haplogroup from one island? the question however remain open for this as well the language hypothesis,origin of the Greeks and previous inhabitants there.