I think simply considering it a pilot program resolves this apparent contradiction.
Another view is that one of the few idealogical commitments of this administration is global bullies doing favors for each other. It's not totally clear to me which direction the favor lies in this one, but I think both sides expect it to be returned at some point.
I think it's a combination of cruelty and drinking their own kool-aid to an extent. They like hurting these people, and some of them probably believe to some extent that all of these people really are dangerous gang members. I doubt they care very much about who pays whom.
Another view is that one of the few idealogical commitments of this administration is global bullies doing favors for each other. It's not totally clear to me which direction the favor lies in this one, but I think both sides expect it to be returned at some point.