ttdtt,
Do remember that you are quoting from the New World Translation. The verse doesn't read exactly like that in the Hebrew.
The Hebrew reads like this:
When someone strikes their slave with a rod, whether they be male or female, and it's the type of beating that results in a death, punishment must be extracted. But no punishment will be demanded where this does not happen. If there is a question, wait a day or two. The slave is the other’s property.
Torah isn't saying that Jews may beat those in their service up to the point of death. On the contrary, Torah is explaining why someone can receive capital punishment for killing their own slave. It is teaching that there is a difference between someone whacking another with a rod and one beating them so badly that they die.
The phrase, "the slave is the other's property" follows the statement LO YUQQAM in Hebrew, which literally means "DO NOT EXECUTE (HIM)." This shows that the subject of the passage is when a slave owner is accused of going too far in beating a slave. Torah is asking: Was this just a passing beating? Was it bad enough to kill the slave?
Torah suddenly skips a few verses to say something else, then continues with the slave issue, stating in verse 26:
When someone strikes the eye of their slave, male or female, causing permanent damage, they must let that slave go free on account of losing their eye. If they knock out the slave's tooth, male or female, they must let that slave go free on account of losing their tooth.
You might notice that there are verses stuck in between speaking about what happens to a slave when a slave owner punishes them. What are these verses? Verses 22-25 are the famous Lex Talinois law, the "measure-for-measure" punishment, the "eye for an eye, life for life" law. They are applied to free people in this instance and then Torah goes back to speaking about slaves. Why?
Torah is saying Biblical law is the same for all classes. You beat anyone, free or slave, and cause any damage, the same gets done to you.
Sure, my people the Jews had slaves, but don't forget, so did yours. How did your people treat your slaves when your Gentile ancestors had them? Were their laws worse or better? What does history say about your culture's treatment of slaves?