Those spaces should be subject to some form of public inspection but there's probably a good argument to not allow random cameras in.

Earlier this year various elected officials tried to perform exactly that kind of public inspection of ICE facilities and met a lot of resistance. I know that some subset of these were just publicity stunts, but despite that, the fact remains that the public needs to be aware of what detention in those facilities is like and if the DHS makes choices that result in random cameras being the only way to do that, then they should reap what they sow.