A "scapegoat" is someone who is incorrectly blamed for someone else's errors or sins. The perspective you're responding to is this: They built the system, they run the system, they have continuously warned "This system is dangerous!", and yet persisted. That is not being incorrectly blamed, not being a scapegoat, and instead is a collaborator.
So I think you mean to ask: "Why do people focus so much on finding someone to blame?" It's not merely semantic, because the answer to that is more straightforward: Consistent accountability is a major factor in deterring bad behavior. It is not the only factor, but it is a major one.
That is my Steel Man understanding of the people searching for individual blame.
Imagine we made nuclear weapons a private industry, had CEOs bragging how they have enough warheads to blow the Earth to smithereens, and then they "accidentally" nuked three cities over a short period of time each, saying they lost control, or rather couldn't contain their semi-autonomous weapon. All somehow managing to turn the PR around from their abject incompetence and towards SciFi visions of mankind hunted by self-replicating bombs.
I, for one, am not trying to find scapegoats or go on a witchhunt.
But managers are paid a lot of money to take responsibility. Yes, that's an old school thought, responsibility. But that's one big reason they get a big, fat paycheck.
Countries demand reparation for damages in war. Citizens of those countries sue for damages and win.
Accountability is not a foreign concept. And the point is to disincentivize negligence. Because negligence is cheaper. And in this case, accidental hacks are marketing spend.