You neglected to, purposely, post the full quotation. Tacitus describes the musing of the origins of the Jews citing what others have said:
"
The Jews are said to have been refugees from the island of Crete who settled in the remotest corner of Libya in the days when, according to the story, Saturn was driven from his throne by the aggression of Jupiter.note This is a deduction from the name
Judaei by which they became known: the word is to be regarded as a
barbarous lengthening of
Idaei, the name of the people dwelling around the famous Mount Ida in Crete. A few authorities hold that in the reign of Isis the surplus population of Egypt was evacuated to neighboring lands under the leadership of Hierosolymus and Judas.note Many assure us that the Jews are descended from those
Ethiopians who were driven by fear and hatred to emigrate from their home country when Cepheus was king.note
There are some who say that a motley collection of landless Assyrians occupied a part of Egypt, and then built cities of their own, inhabiting the lands of the Hebrews and the nearer parts of Syria.
Others again find a famous ancestry for the Jews in the Solymi who are mentioned with respect in the epics of Homer this tribe is supposed have founded
Jerusalem and named it after themselves."
In the full quotation, Tacitus says that Jews might be from Crete, ancient Assyria, or related to Homeric epics. Ethiopia is just among those places that contemporary persons during his time had said Jews may be from. Tacitus, being the historian he was, simply lists all of the places that Jews may be from.
But then - in the following paragraph, Tacitus says the following:
"
Most authorities, however, agree on the following account. The whole of Egypt was once plagued by a wasting disease which caused bodily disfigurement. So
pharaoh Bocchorisnote went to the
oracle of
Hammonnote to ask for a cure, and was told to purify his kingdom by expelling the victims to other lands, as they lay under a divine curse. Thus a multitude of sufferers was rounded up, herded together, and abandoned in the wilderness. Here the exiles tearfully resigned themselves to their fate. But one of them, who was called Moses, urged his companions not to wait passively for help from god or man, for both had deserted them: they should trust to their own initiative and to whatever guidance first helped them to extricate themselves from their present plight. They agreed, and started off at random into the unknown. But exhaustion set in, chiefly through lack of water, and the level plain was already strewn with the bodies of those who had collapsed and were at their last gasp when a herd of wild asses left their pasture and made for the spade of a wooded crag. Moses followed them and was able to bring to light a number of abundant channels of water whose presence he had deduced from a grassy patch of ground. This relieved their thirst. They traveled on for six days without a break, and on the seventh they expelled the previous inhabitants of Canaan, took over their lands and in them built a holy city and temple.
"
Essentially, Tacitus points towards an Egyptian origin of the Jews, spends the most time describing that account (2 paragraphs) and not just a throw away line about Ethiopia.
