Did you? Apparently by statute
Even the Immigration and Customs Enforcement (ICE) questions the need to hold all these people. Many people picked up by the immigration authorities are in the middle of regularizing their status or are firmly rooted in their communities, not about to disappear. The Obama administration has directed the ICE to focus only on undocumented persons who have criminal records, not on ordinary workers. But, by law, the ICE must hold 34,000 persons every day.
But they must hold 34,000 -- by law. Why? Well somebody is making a profit on this travesty:
I've realized the consequence of his policy -- the enforcers need to fill quotas of inmates -- explains why appeals to the ICE to let immigrants out on bail sometimes succeed. Immigration raiders are only grabbing them to keep all 34,000 beds filled.