Are we still so sure that they no longer care for capturing humans?
And …
That might just be a temporary thing and all inhabited systems with active Titans get that, hard to tell with a sample size of 1. Or it might be more serious than that.
I have not been entirely convinced they were going to abandon Sol even after Cocijo’s destruction - which, if it doesn’t abandon its location just before destruction or if it stays in place in the event of surviving to maintenance, should Frontier not fiddle with numbers from here, is all but assured - so maybe they won’t. (And we know the fleet which accompanies the Titan usually remains in system for another 1-2 weeks before departing, after destruction.)
There certainly seems to be little strategic value I can see in them continuing to attack Mars High, as its value as a staging point is limited and less practical than finding a nearby system to jump to and fix up at a carrier around a star. Two reasons I could see is looking to make it as unappealing as possible for humans to return by thoroughly wrecking the infrastructure as much as possible, or “encourage” evacuations with that remaining battered port for their own purposes (abduction).
Let’s also not forget what Seo said about the captives - that they are “important to the next phase of the Thargoid war”… and they act long term. So, I guess we might soon find out what they were for… or are for, rather.