Isn’t that what Palantir’s product is?

They probably use Excel, maybe Microsoft Access.

I think you meant one shudders. And yeah, Snowden made it clear there's orders of magnitude more data than this graph explorer for them to sift through.

Software like i2 Analyst's Notebook.

Internet search engines have their origins in government projects fwiw. They had search engines before Alta Vista, used for searching data sets that pre-date the internet, and some of the people involved in those went to work on the original commercial search engines.