Defamation requires the claim to be both a lie, and made publicly. The tool needs to be run locally, and specifically tells you that it’s searching by name and that others with the same name will be found in the results, and that’s why it gives the context and lists where in the files it came up.

So the tool itself isn’t defamatory, but anyone that uses is better be damn sure that they have the correct person if they start publicly talking or writing about what it finds.