Let's use some logic here, instead of quotes. An unqualified HR department that does not have proper procedures in place may not notify or relay all of the facts to other parties.
Using your logic, if I'm in charge of HR and simply sweep complaints under the rug, it's not my fault because other people should know what is going on.
No, it's your fault for sweeping it under the rug. But it's also the fault of people above you for allowing a culture and an out-of-control department where stuff gets swept under the rug.
No. I am saying that the CTO is responsible for knowing what is going on in his/her departments, full stop. "Knew or should have known". If the CTO doesn't know, it's the CTO's fault for not knowing, because it's the CTO's job to know.
Now, if you have one employee go off the rails, it's not the CTO's fault for knowing in advance that the one employee had problems. But a department-wide issue? Yeah, it's the CTO's job.
Using your logic, if I'm in charge of HR and simply sweep complaints under the rug, it's not my fault because other people should know what is going on.
Brilliant.