It’s an evil service and no matter who requests it or supplies it, doing so is an evil act.
No, you are. I'm implying evil are (primarily) those who use it, not (just) those who make it. You can try to make whatever you want, if nobody will buy it, then you won't have money to make it. Palantir only exists because governments are evil and willing to buy it. If you want Palantir to not exist you need to hold your government accountable.
Are gun makers evil and responsible whenever someone gets killed by a murderer, or are those who pull the trigger responsible?
Yes. There's a reason Remington decided to settle for $73M dollars with the sandyhook parents even though they didn't "pull the trigger" [1]. That's not a number you pick because you think you'll win the case.
[1] https://abcnews.com/US/sandy-hook-families-settle-remington-...
It's only because of how the legal system works in the US, with ambulance chasing lawyer and where cases are decided on the emotions and societal moral panics of the people in the jury and negative brand image such cases can cause, not if someone is objectively right or wrong.
Meaning it's cheaper to pay people off even if they're legally wrong, than try to prove you are right but then deal with the bad publicity of the mob with pitchforks and torches who blames you for their kids dying. Keep in mind parents of that time also blamed violent videogames like Doom for it, so it's not like they were right about who was to blame, they were just looking for retribution from anyone they could.
Palantir were in no way obliged or coerced into making an evil thing, they just decided being evil for money was ok.