While rarely are workplace harassment complaints falsified, the reality for employers is that employees may not always understand what conduct is actually within bounds.
For example, while extreme forms of performance management may constitute harassment, this does not mean that all performance management immediately falls under that umbrella. Health and safety legislation explicitly states that reasonable management activities will not constitute harassment. For employers, it means that they should not need to worry about providing critical or constructive feedback, so long as they are doing so fairly.
The unfortunate reality is that not every employee will succeed in their role. Implementation of a performance management plan or performance improvement plan is also not harassment so long as it is done in good faith. If the employee is not successful after this, an employer can still elect to let the employee go, although in most cases this would be a termination without cause.