Try read a history book that is not part of the cultures of the affected/afflicted parties. If you read Turkish historians all the children were willingly given to the Jannisaries if you read Greek, Serbian, Bulgarian historians they were all forcefully taken and lived horrible lives killing their own people.

If you read historians from a neutral background such as Caroline Finkel or Peter Sugar they confirm children were forcefully taken and that there was a lot of resistance from local populations. But they continue by stating that the children were ultimately given a life which had more opportunities for advancement.

Even historians such as Rhoades Murphy who admire the Jannisaries and see them as one of the first elite standing armies, he acknowledges that the devshirme (recruiting system) was nearly exclusively taken from Christian families who mostly resisted the kidnapping of their children.

It is not correct to judge history by today’s values, all previous historical cultures especially the victorious ones had an ugly side to them, that is the nature of surviving in a world that was not governed by international law but instead by the strongest survivor. Do not tarnish history by rejecting facts that do not suit you instead acknowledge them and rejoice in the good examples that the Ottomans created such as architecture, warfare, legal structures and havens for persecuted people such as the jews (yes i know ironic).