and trying to dump them into the USA civilian legal system to "stand trial"

No, they'd still be kept in indefinite detention without trial, but on American soil. That's the reason that several progressives voted to block the move, because it would've established further precedent to expand those conditions into the US. It wouldn't have given them a fair trial (by US standards) or stopped torture, it would've just allowed them to be held without trial and tortured on US soil.