What it shows is managerial insecurity. Despite the obsession with monitoring "productivity", managers really haven't the faintest idea of what they're doing.
A healthy relationship is one in which managers don't monitor and don't micromanage and don't rely on Jira or commit logs to lazily monitor employees. A manager isn't there to lord over employees. He is there to support employees and help them do their jobs. But to do that, you need to know what they're doing.
Talk to them. Listen. Hold 1-on-1s on a regular basis. Assume they're doing their jobs instead of defaulting to a defensive and adversarial posture. If you treat employees like adversaries, they'll behave like adversaries. Grant them reasonable trust and they will take initiative and view the relationship as one that is cooperative. They will be less likely to want to risk losing the reasonable trust they have been gratuitously given; if you default to suspicion, then employees have little to lose. You already think poorly of them, so who cares.
If someone is genuinely slacking or not well-suited, that will come out sooner or later. 1-on-1s, individually and taken in aggregate, will give the manager an idea of what is really happening, especially if the manager is competent and knowledgeable of the domain, which he should be. 360 EOY reviews can also help here, not as an adversarial tactic, but as a way to share feedback. A competent manager can read the tea leaves.