Why would it be unbelievable? Because we see certain parts of Islamic practice and fiqh IRL, that had been "forgotten and ignored" for a long time? Don't forget the reward for bringing back a sunnah of the pbuh. There are some specific mention of the honour and reward for it in a hadeeth, but my sub-conscious has made me hide it away somewhere in my memory bank.
These ARE actual fiqh rules, and students and scholars who advance in their studies all learn it. Even though I never reached there to get into the whole fiqh of slavery, there were a lot of redundant fiqh rules for modern life we asked why we had to memorize it. "Because you never know if you will find yourself in a situation when you need the knowledge". Alhamdulillah, we had a scholar available for our recent slavery issues in the khilafah.
And don't forget. These are THE rules and regulations that makes Muslim apologists claim how just and merciful Islamic slavery was. Well, now it's up for the test