1. The Egyptians still had freedom of choice.
2. Slavery was decreed, torture was not.
3. The Egyptians' motivation was wrong.

Although the fact that the Jews would be exiled in Egypt was predicted, nevertheless each Egyptian as an individual still had the freedom to choose whether to participate in the oppression or not. G-d's Divine decree does not necessarily remove the individual's free- will. (Maimonides)

1. The Egyptians still had freedom of choice.
2. Slavery was decreed, torture was not.
3. The Egyptians' motivation was wrong.

Slavery was indeed decreed by G-d, however the excessive persecution of the Jews by the Egyptians was not, and hence they were punished for their cruelty but not for the actual enslavement. (Nachmanides)

1. The Egyptians still had freedom of choice.
2. Slavery was decreed, torture was not.
3. The Egyptians' motivation was wrong.

Had the Egyptians enslaved the Jews in order to fulfill the Divine decree they would not have been punished. The Egyptians intent in enslaving the Jews was for personal gain and not for altruistic reasons.Thus even though their actions were "legal", because their motivation was evil they deserved punishment. (Nachmanides)