Science

From your link:

By July 2019, most astronomers concluded that it was a natural object, but its exact characterization is contentious given the limited observation window. While an unconsolidated object (rubble pile) would require ʻOumuamua to be of a density similar to rocky asteroids

On 22 March 2023, astronomers proposed the observed acceleration was "due to the release of entrapped molecular hydrogen that formed through energetic processing of an H2O-rich icy body",[33] consistent with 'Oumuamua being an interstellar comet, "originating as a planetesimal relic broadly similar to solar system comets"

Avi Loeb has suggested that it could be a product of extraterrestrial technology,[35] but there is insufficient evidence to support any hypotheses, "despite all [its] strangeness".

While basically every Astrophysicist agrees it is from outside our solar system. He is basically the only Astrophysicist who believes it is an artefact of alien intelligence and design.

While I have not read his book it sounds like a case of confirmation basis on his part.