My take on SEA Source has always been that the Corp is specifically asking SEA for data on network information at a specific time and place, backtracking from the point of known incursion until they find the Runner.
So, the narrative forms:
Hacker jacks in, runs the Net, finds the upcoming agenda, some kind of Project, Atlas holding the world or something. Instead of accessing it or releasing it themselves, they forward the info to a buddy of theirs, a popular Film Critic. The hacker jacks out and then goes to talk with the Critic for a little while to get them to post it on their blog, and after a bit of time, enough info is out in the open that the public knows, and the Corp is setback.
So the next morning, the Corporation can't enact a Punitive Counterstrike, since the public face is a popular Critic, even if the Corp knows that guy couldn't have been the hacker. For the same reason, you can't Replace your Midseason lineup, because no one's heard of the actual hacker. However, SEA has been able to Source the location of the network traffic, for a fee of course... And that's where you can have Lizzy enact some 'urban renewal'.