Most of these departments have rules about how they use our data. ICE now gobbles it all up and can use it without rules by a department that operates with little regard and lots of exceptions to typical protections for citizens afforded by the constitution.
The majority in SCOTUS does not seem to care (it’s ok as long as their guy does it). Whatever rules we thought there were seem to be out the window because someone magically moved data or ICE got to do it or so on ...
Yes, but law enforcement agencies can typically be granted access for investigations, so long as the information is used only for such investigations. This is how CSAM distributors are hunted down. They don't literally need to amass evidence for each and every suspect and then get a warrant: they have a legally recognized enforcement directive, and so can perform surveillance of information sources where that people breaking those laws can be caught. Or in this case, they may have imperfect information on a variety of actual suspects, but not enough to find them or build a case. Medicaid data may provide those clues.