There's a difference between:

• The Federal Government spying on people & detaining dissidents
• Palantir conducting espionage & harvesting data from everybody

The first one is more by the government in which they have legislative power to enforce rules on the population (which is something Palantir does not possess) also giving power to both LE and the judiciary on detaining people. Usually, it's a politician who creates these laws for their own gain. It's already been done using AV under the excuse of "think of the children" when the truth is closer to deanonymizing the internet.

The second is done by a private company, like Palantir: they do not carry legal power on detaining people as they are not the police nor the justice system. The only thing they can do is harvest data from people and monitor them, but even if they witnessed something "illegal" they still can't arrest or imprison people themselves (while both the government or NSA has that leverage as five eyes are already doing that).