Palentir has certainly assisted, but the origin of the data collection here was public and then unleashed by the state to private entity.
Yes, it's surely public information and therefore ought to be subject to the same controls as any other personal health information. It seems moot that it was given to a private company; the issue just shifts to being that the private company (apparently) does not comply with data protection laws, e.g. HIPAA.
Does this imply that undocumented aliens subject to deportation have been making claims on Medicare/Medicaid monies?
No. HHS is broader than CMMS.
Like, if these data were being used to audit the CMMS roles for illegal immigrants, that would be something. That’s not what DHS is doing because I suspect they don’t want to have to produce a report that says this was a made-up bit of electioneering.