Those who know better please correct me. My current understanding of Palantir (and other surveillance tech companies like Peregrine) is:
1. They facilitate the sale of data to law enforcement, enabling the government to circumvent fourth amendment protections.
2. They fuse cross-government agency data through Foundry and fuse them into unified profiles which the government can use to surveil and pressure citizens without probable cause or a warrant.
ICE also uses a Palantir tool called ELITE to build deportation target lists.
EDIT: Downvoting my comment without any proper rebuttal or clarification is pretty silly.