Is a person obligated to risk their own position in that system for the sake of someone else? Legally, no. In many ethical systems, also no.

You claimed that people who are not taking action are complicit. Often that is absolutely not the case. Often in fact those people are helpless, bound by their own situations.

Let's take the example of a mugging. You walk past an alley, and you see someone pointing a gun at another person. Are you obligated to intervene? Of course not. You might be able to save that person's life or defuse the situation but you also just might get killed and accomplish nothing.

Let's take another example. Workplace bullying. You witness a person who is being very aggressive to a coworker, giving insults and maybe even being physical. Do you intervene? Of course you do, right?

Now imagine you have kids. Your spouse recently lost their job, you can't afford to also lose yours. Surely you wouldn't be risking your job by speaking up about this bullying right? Except the bully is your boss. And he's good friends with the CEO. But that's what HR is for right? You make an anonymous tip to HR. And nothing happens because HR won't act on an anonymous tip. So you should talk to them in person right? But that's putting yourself at risk and boy you really can't lose your job.

Helpless. Not malicious.