Slavery is bad if you are not god’s favorites

Exodus 3:7 says, “And the LORD said, I have surely seen the affliction of my people which are in Egypt, and have heard their cry by reason of their taskmasters; for I know their sorrows;”

 Didn’t I read a while ago that the Hebrews had slaves?  I guess god doesn’t hear their cry.  Maybe the Israelites were nice taskmasters, but isn’t slavery wrong to any slave?  I wish we could just ask Bilhah and Zilpah, who were Jacob’s servants (slaves,) and ask them how they felt as they were impregnated by their taskmaster.