What passage in Leviticus are you referring to? The Jews were required to free all their slaves at the Jubilee year. This command can be found in Levitus chapter 25. All slaves were to be given their freedom after seven "sevens" of years.
Like I say in the article, I do not believe that physical slavery is the main issue to God. It is spiritual slavery that is repugnant to God. Nevertheless, God clearly does not agree with the abuse that is almost always associated with slavery, which is why he limited slavery for the Jews.
In any case, I cannot respond to your claim unless I have the passage you are using to prove that slaves could be held forever. I am rather confident that passages about the Jubilee year should be taken into account, and that your conclusion that Jews could hold slaves for perpetuity is not correct.
Please let me know.