I think it’s important to say that they also protect from rogue/drive by superstar IC’s. The ones who will come along and “fix” your problem, leaving a mess that nobody understands behind them that makes them look competent and your team incompetent, when in reality they’ve just half assed the job.
I’ve seen managers stand up for their teams and defend against those guys successfully.
It really reveals how clueless some managers are when they sing praises of the "rockstar" IC who from day 1 trash talked their coworkers and broke everything they touched before leaving after a few months to do the same somewhere else.
It shows how managers often just base their opinions on vibes given in meetings and don't care to understand anything they're managing.
I’ve seen managers stand up for their teams and defend against those guys successfully.