I agree. Impractical, in today’s world, but certainly not immoral when used as a punishment, as it was in the time of the Israelites.
Permanent (especially hereditary) involuntary servitude, in all parts of the world and at all times, is wrong.
Not at all. Think "20 years of hard labor" or even a weekend picking up trash along roadsides. Those are both instances of involuntary servitude. I don't believe it moral to sell this service, however, as is done in Chinese prison labor. That changes it from punishment by a sanctioned societal authority to enslavement for profit.