Well that's clearly an example of putting the cart before the horse. You should be able to sleep at night so long as you remember that Git isn't what enables Palantir to power an army of federalized brownshirts; it's the people making the tools explicitly for an army of federalized brownshirts with Git that are morally culpable.
Okay, that's where you draw the line. But someone provides power to their data center and their offices. Someone provides hand-held devices. Someone provides network connectivity. Someone has a contract to house and feed these agents. Someone has the logistical and fleet services for their vehicles. Someone is likely the landlord to their buildings. Someone has a contract to clean the buildings. Someone is a deciding to buy a block of Palantir stock versus some other software company. Someone runs the private prison into which people are herded. An attorney has a choice to file a charge or not file a charge. A judge has the choice to bend over backward to give ICE/CBP the benefit of the doubt, or be skeptical.
Baking a roll of bread is not immoral. Baking bread as part of a contract to feed the gestapo, is.