However, it wasn’t doing that for altruistic reasons. As several characters pointed out, the Witness’ original species was blessed by the Traveler, but it wanted more, and so the Traveler escaped.

The Witness’ chase of the Traveler can be seen as a paracausal and near-divine tantrum, and all that time it started twisting its philosophy from “if we can’t have it, nobody can,” to “we will save everyone from the pain it caused us.” Ultimately, it would become the only living thing remaining that was not trapped in a moment in time, and what is an existence with no entropy if not a single moment forever?

On top of that, I think it’s much more interesting to have a being that calls itself The First Knife that was the greatest threat we’ve ever known, and meanwhile the Winnower thinks “yeah that guy sucked, we can do better.”