We have been on Cradle for years now and there has been no action to locate the laser cannons that destroyed our ship and to disable them.
I can understand the reasoning behind not attempting to call for help (from other starships) due to the fact that the lasers would merely shoot down that ship as well, however I don't understand why we have not decided to pursue a campaign against these weapons.
The only viable explanation is that the Core powers the lasers and the entire mechanism (including whatever electrical lines power it) is completely indestructible. Considering the current state of many of the machines and constructs on Cradle I find that also hard to believe.
I want to believe it was the gremlins, or more likely the swarm. If it were the gremlins, then it would make more sense for us to wage a war on them. If it were the swarm, then we have quite the issue on our hands.