Parshas Mishpatim opens with the halachos of eved Ivri, commonly translated as "Jewish slave". In this context, however, the word slave is misleading. The Torah demands that the Jewish "slave" not be assigned demeaning work, that the food, drink, clothing and lodgings provided him be the equal of his "master". The Torah's demands which ensure the dignity of the "slave" are so great that Chazal comment, "anyone who acquires a Jewish 'slave' - it is as if he has acquired a master for himself" (see Rambam Hilchos Avodim chap. 1 for all of the above.) Clearly, the life of the Jewish "slave" has nothing in common with the misery of Uncle Tom. Hence, the translation is very misleading. Perhaps an alternative (admittedly, ineloquent) is "a Jewish laborer bound to a long term commitment."
And yet, the translation Jewish "slave" is not wrong. The lashon hakodesh word eved does carry some of the same connotation as the English word slave. But why would the Torah depict a Jewish laborer bound to a long term commitment under the best of conditions (see above regarding type of work and quality of accommodations) as a slave?
On the most basic level, the Jewish slave can not refuse any non-demeaning, fair assignments. There is an element of slavery in the long term curtailment of his options. On a deeper level (what follows is based upon and inspired by a dvar Torah I was privileged to hear from HaRav C.Y. Goldvicht zt"l, late Rosh Yeshiva of Yeshivas Kerem B'Yavneh), the eved Ivrei is prone to developing a slavish mindset or mentality. A slave does not aspire to spiritual heights, to kirvas Elokim, because he feels constrained by his time commitment and work obligations to his master. In terms of material provisions and accommodations he is free, but in terms of spiritual growth and aspirations he is enslaved.
The Torah teaches that the institution of eved Ivri can only exist at a time when the mitzvah of yovel is operative. Hence, we no longer have Jewish "slaves". And yet the specter of Jewish "slavery" persists. When an employee feels a sense of dependence on his employer (and not Hakadosh Baruch Hu), he becomes enslaved, with the pursuant loss of spiritual freedom. Satisfying his boss becomes the paramount concern, even to the point of acceding religious compromise or mediocrity. When due to social influence or pressure we simply fall in line with everyone else in terms of questionable religious habits (coming late to shul, how much time is devoted to learning, dress, etc.) we are enslaved.
The parsha of eved Ivri teaches that we have to be free of any contractual commitment or other type of entanglement that may constrain our avodas Hashem, or even aspirations within avodas Hashem. Any sense of dependence on others impinges upon what should be our exclusive, absolute dependence upon Hakadosh Baruch Hu. Accordingly, Hakadosh Baruch Hu insists that the rightful state of affairs is that avodai heim, v'lo avodim l'avodim.