As we know we need to separate islam and muslims who are humans who make mistakes. Islam allows slavery under certain conditions, slaves can be taken only through war and should be treated in a humane way, freeing slaves is also highly encouraged. The arab slave trade deviated from these principles in during the ottoman era and after that.
After this introduction I still have a doubt, the first khilafa al rashidun engaged in slave trade against innocent people who never attacked the muslims. For example in the 7th century under the caliphate of Umar al khattab the arabs conquered egypt and attacked nubia, the nubians resisted against the invasion but they were forced to sign a treaty known as baqt that forced them to send 360 slaves every year to the muslims. How can Umar Al khattab allow such a thing? arab attacked first, it wasn't a defensive war. The rashidun caliphs were sahabas so they are supposed to be the best people after the prophet. In the following centuries arabs engaged in slave raids against innocent people like the zanj of east africa(swahili coast) who never attacked the muslims.
After this introduction I still have a doubt, the first khilafa al rashidun engaged in slave trade against innocent people who never attacked the muslims. For example in the 7th century under the caliphate of Umar al khattab the arabs conquered egypt and attacked nubia, the nubians resisted against the invasion but they were forced to sign a treaty known as baqt that forced them to send 360 slaves every year to the muslims. How can Umar Al khattab allow such a thing? arab attacked first, it wasn't a defensive war. The rashidun caliphs were sahabas so they are supposed to be the best people after the prophet. In the following centuries arabs engaged in slave raids against innocent people like the zanj of east africa(swahili coast) who never attacked the muslims.