All airports at which the TSA is located are government owned and are thus subject to the restrictions imposed by the Constitution, which includes the right to take photographs in publicly accessible spaces. Private shopping malls are not owned by the government and, for the most part (California being one of the exceptions if I recall correctly), are not subject to the restrictions imposed by the Constitution on prohibiting photographs.

As an aside, the TSA has said in its discussions about photography that we are not permitted to take pictures of the x-ray monitors. I have read the implementing regulations and have discussed the same with a TSA attorney and know this is not the case. The x-ray monitors are considered to be SSI, so "covered persons" are not permitted to take pictures of them and are to protect that info. However, regular passengers do not fall under the "covered person" definition and, as such, are not subject to the requirement. So a TSO (or an aircrew member) would not be permitted to take a picture of an x-ray monitor, but the general public can without restriction.