I worked for a manager that would use "I exited his ass" as a badge of pride. That shows no respect for the person, and it also shows no due diligence and hiring, mentoring or coaching that individual.
We all have our own particular biases in how we measure our own personal success, and as leaders we also apply our biases to how we interpret other's success. As a leader who has control of someone's livelihood, you should ensure a tempered layering of (1) expectations, (2) feedback, (3) understanding, and (4) mutual understanding of fit.
No one should be surprised that they are getting fired or getting on a performance plan. The silent behavior is a tell, but it is ultimately unfair to the employee.
Bad hires do happen, but it's usually pretty clear and pretty mutual when that happens.