Actually, the earliest rabbinic sources present the Greek translation (the Septuagint) in glowing terms. In the Mishna, Megillah 1:8, Rabban Shimon ben Gamliel is quoted as having said that Greek is the only language, other than Hebrew, in which it is permissible to write sifrei Torah. Commenting on this, the Jerusalem Talmud (Megillah 71c) says that the sages checked and discovered that Greek is the only language into which it is possible to translate the Torah with its exact meaning.
Likewise, in the Babylonian Talmud (Megillah 9a), the origin story of the Septuagint is presented, and one which testifies to the miraculous nature of its composition. This origin story is very similar to the earliest extant text that testifies to the Septuagint's composition: a pseudepigraphic Jewish letter that purports to be written by Aristeas, King Ptolemy's bodyguard.
The reality is that, by the time we come to the composition of the extracanonical tractate, Sofrim, the attitude had changed rather dramatically. There, in Sofrim 1:6-7, it is explicitly said that sifrei Torah cannot be written in Greek, that it is impossible to translate the Torah into any other language without changing its meaning, and that the day on which the Septuagint was written (by no more than five elders!) was as hard for the Jewish people as the day on which the golden calf had been constructed.
The reason for this change of attitude lies in the fact that the Septuagint (which, in time, came to denote the translation into Greek of the entire Tanakh) was embraced by the nascent Church and used in anti-Jewish Christian polemic. A favourite in that regard was the translation of Isaiah 7:14, in which עלמה ('almah, "young lady") was rendered παρθενος (parthenos, "virgin").
By the time of the composition of minor tractate Sofrim, Christians had composed a number of anti-Jewish tracts, which utilised the Septuagint for the purposes of demonstrating Jewish stubborness in their rejecting Jesus. Perhaps the most graphic of these texts was a 6th century text (the same century in which Sofrim was composed), titled Disputatio cum Herbane Judaeo: "Disputation with the Jew, Hurban [from the Hebrew word, Destruction]". The author identifies himself as Bishop Gregentius of Tafra, in Yemen, but is only adopting that persona for the purposes of the text.
In it, he attributes the following sentiment to his invented Jew, Hurban:
Our fathers wrongly and capriciously translated the books of Israel
into Greek so that you could take possession of the same and silence
us.
- Martin Hengel, The Septuagint as Christian Scripture: its Prehistory and the Problem of its Canon (ed. David J. Reimer; Edinburgh & New York: T&T Clark, 2002), 35.
With such attitudes as these, it was no wonder that the Jews came to view their Greek translation as a tragedy, to rule it out altogether as a liturgical text, and to undermine the earlier texts that spoke of the miraculous nature of its composition.
- Emanuel Tov, "The Septuagint". Pages 161-188 of Mikra (ed. M.J. Mulder; Philadelphia: Fortress Press, 1988) - p163 in particular;
- Norman Gottwald, The Hebrew Bible: A Socio-Literary Introduction (Philadelphia: Fortress Press, 1987), 121-122.
See also: Oded Irshai, "Confronting a Christian Empire". Pages 181-221 of Cultures of the Jews: A New History (ed. D. Biale; New York: Schocken Books, 2002). On p.203-204, he describes an attempt by Justinian in the 6th century, to ban study of the Mishna and to enforce that all Jews under his sphere of influence utilise the Septuagint if reading the Bible in Greek.