It certainly does not seem to be in the interest of the current US government.
To answer your question:
Protecting a whistleblower's identity is in the interest of US society as a whole. It protects the individual somewhat from persecution which in turn encourages people to blow the whistle on illegal activities, thus benefiting society.
If the last four years have proven anything, it's that the US gvt. is not a monolith. The three branches of the government are further subdivided into bureaus, agencies, committees, and regional subdivisions, all with their own distinct interests and concerns. The president may be the chief subject of public scrutiny at present, but that doesn't mean other interests within the state should be immune to scrutiny.
I can't claim to know anything about ciarmella's background, save what hyper-partisan, conservative outlets have spewed. But absent more even-handed coverage, or rebuttals from liberal and left-leaning outlets, the details of his personal history, and affiliations do seem to merit some level of public scrutiny. Anyone interested can look him up on Breitbart, conservapedia /wikispooks, or through any other connservativr outlet (oddly enough, not fox last time I checked). But I'd rather not link to those rags if I'm not confident of the veracity of the information within.
Still, it's redacted due to some interesting parties pressing charges. Protecting a whistleblower's identity is the right thing for sure, but I don't believe Google add his name on the list for the righteous reason.
To answer your question:
Protecting a whistleblower's identity is in the interest of US society as a whole. It protects the individual somewhat from persecution which in turn encourages people to blow the whistle on illegal activities, thus benefiting society.