I disagree, for example, I quoted a verse, that shows it was not allowed to keep the war captives as captives after the war settles, and even during the time, either free them by ransom or generosity. And there other verses that even give the condition, if they accept Islam after being captive and pledge to not fight Muslims to let them go.
Then there are even verses about what happens, if you let them go, and they go fighting Muslims again. Even there it says, as for those who leave Islam, but now, don't want to fight Muslims, to let them go and if they offer peace to not fight them.
So this was during war, and after war, it's clear the verse I showed, to let them go. And even captives are not allowed for a Prophet ever unless there was massive slaughter in the land, in case, it becomes necessary. But like I showed, the verse, clearly says to let them go when the fury of war is over.