While you’re right that the orcs were clearly in the wrong and deserved punishment, the camps were not created for the orcs to just slave their days away.
King Terenas Menethil II and the Council of Six of Dalaran hoped to rehabilitate the orcs and make them citizens of their kingdoms, alas the orcish lethargy happened and they were unable to cure the orcs from that. As such rehabilitation was unable to happen and the orcs were detained for way longer then (possibly) nessecary.
This was never the plan, though. The lethargy caused, orcs didn’t work anymore and if the Alliance would’ve just let them go they’d either join one of the surviving orcish raider clans/warbands and restart the conflict or they’d be so lethargic they’d starve themselves and their family to death.
The Kirin Tor was hard at work searching for a cure for both the lethargy and the Fel that still influences the orcs to this day.
This, while what the orcs did was inexcusable (esp since they did it before drinking the Felblood), the draenei dug their own grave by not warning the orcs, ogres, arrakoa and other races of Draenor.
To be fair, the human tribes tried to eke out a living after they were attacked, murdered and exiled by the vrykul, the forest trolls however attacked them immediatly too, after the humans lost the protection of their Titan Keepers and vrykul parents. Humans had no choice in this regard (unlike the high elves who still decided to settle in Amani heartland even after they discovered they settled on sacred troll lands, but the conflict between trolls and elves is as old as trollkind so ).