It was established in
Watching the Clock that the First Contact incident was the result of the Sphere Builders making a second attempt at their "destroy the Federation by taking out Earth in the past" scheme. (It's nice to see that villains are allowed to try the same plan more than once, rather than being Saturday morning cartoon adversaries, so to speak

). This time, the Sphere Builders seem to have picked a race that can't be made to eventually question their motives and turn against them. It occurs to me that the Sphere Builders, if they know about
Columbia, might be very clever here - are they trying to remove not just one threat to their colonization attempt but two? Create a timeline free of the Federation
and the Borg? Killing two birds with one stone? Their patsy is going to ensure its own absence from the new timeline, as well as the UFP's? Leaving the two largest threats to Sphere Builder control of our realm non-existent?