I'm pretty sure you're wrong about that last part. There were a lot of slaves taken as devşirme from various parts of Europe and Anatolia. Most of them became soldiers but the ones who did the best on the exams they were given became bureaucrats instead. And so the Ottomans became the second state, after China, to choose its bureaucrats by exam and gained all the advantages that implied. The system decayed, though, and the whole thing was over by around 1700.

There was certainly sexual slavery in the Ottoman empire too. But it was more common after 1700, the people taken were mostly from the Caucasus instead of Eastern Europe, and it involved far fewer individuals.

Paderasty was indeed common in the imperial palace. How much of that was forced, slavery-like relations are beyond me though.

Isn't there slavery (sexual and otherwise) everywhere islam went ? I mean, the prophet kept slaves (and had extramarital sex with some of them, and this is not doubted or controversial). He also forced some of his other slaves to work, and he confirmed the right for an owner to do whatever he wanted with his/her slaves, including controversially kill them without the need for an explanation.

Why would it be any different in the Ottoman empire ?

First of all, I did not say slavery did not exist in the Empire. It did. But the Janissary/Devsirme is not it. IDK much facts with their proofs about slavery in the Ottoman Empire or Islam, but I doubt the truth of your statements. I'm not here to defend the religion or the empire, but I have never heard of those things (except the liberated Zayd), and I'd be reluctant to take religious myths and gossip as literal facts, especially if there are doubts the people we're talking about ever lived. Then, even if we accept your affirmations, there's no reason to believe that it inevitably causes the Empire to behave in a certain way. Moreover, slavery existed in almost all parts of the world and for the most of our common past, and even made its way into the 20th century in some. So tieing it to a religion is not really logical. I think of religion as a consolidation of a people's tradition, and looking at Ancient Greek and Ancient Mesopotamian literature, it's not hard to find where slavery comes from in the Eastern Mediterranean.

Returning to the original topic, the devsirme is nominally slavery, but the substance of the phaenomenon is not really. And some sultans practiced paderasty, but again reducing the devsirme to a periodical collection of homosexual male sex slaves is just not correct. We're talking about the most powerful men in the Ottoman society for the entire existence of the Janissary/Devsirme system. On many occasions they decided and/or dethroned sultans. Many devsirme dynasties obtained immense power and wealth. The Sokollu family ruled the empire for decades and decades. Mehmed Sokollu created the Bulgarian Church and made his brother the patriarch. Until Mahmud II, not bribing the Janissaries enough meant death for the sultans. Now don't tell me these men were succumbed into a system of involuntary rape by that one guy which they get rid of when they want anyways.

This happened from about 1350 to ~1700, and "staffing sultanate services" mainly meant military and civil service. Repugnant by our modern standard, but somewhat progressive compared to their contemporary empires.

Yeah what else did Sokollu/Sokolovic did other than blowing the sultan? /s

Almost all of the brilliant men of the empire were devsirme. Janissaries were too. You might have some funny anger at dead rulers from centuries ago for whatever reason, but reducing the most powerful individuals of the eastern mediterranean during most of the past millennium to sexual slavery is a bit too much.

Slave soldier systems have a long history in the Middle East; Ottoman Janissaries was by no means the first.

The Ottoman Janissaries were generally the best troops fielded in the late Middle Ages and a large component of what allowed the Ottomans to dominate the Near and Middle East. Like many military castes, however, the Janissaries ended this means of recruitment (as it diluted the power they accumulated) and became a powerful ossified force that retarded needed modernization, happily killing off any sultan that dared resist them, only stopping (temporarily) when the Ottoman royal line was in real danger of running out of successors.

The Ottomans also liked to take Circassian slaves (whom were known for their beauty) and would end up in the harem.

It's why the last emperors looked as they did.

https://en.wikipedia.org/wiki/Mehmed_V

My root is coming from Circassian. Circassian girls are famous for their beauty. This is not only true for Ottomans but nearby states at that time and Harem is completely different story.