This is a terrible, incendiary headline. They're using AWS to host things - big whoop.

"All of that data and the algorithms powering ICM are now being migrated to Amazon Web Services (AWS) in their entirety; Palantir pays Amazon approximately $600,000 a month for the use of its servers, according to the report’s authors."

If it was on-prem would they then be targeting the Cisco, or IBM, or whatever servers used to host the same content?