Regardless of one's political opinions, it seems relatively uncontroversial that answering the question "how is
A not
X?" with the followup question "how is
A,
X?" has contributed very little to the conversation. "
X", in this case "cruelty", might be a debatable quality, but it isn't as though we have no information about the situation. Google is chock-full of different arguments for and against Manning's various punishments. (No links from me, because that would make my opinions obvious.) If you were genuinely curious, that would have been a place to start.
The original question seems fine as a conversation starter, since for one thing it identifies a particular motivated action that most humans would agree is cruel: 'admittedly imprisoning someone for "coercive" reasons', but if the only responses it had inspired had been more meta-conversation like yours then it would have been suitable to flag the whole subthread. Fortunately there were lots of thoughtful responses.