In my view, yes! Why? Losing a job is one of the most stressful, emotionally wrenching, financially harmful things that can happen to a person. When terminated employees think they are doing everything right, not telling them the reason leads them to try to make sense of it. That leads to discrimination and retaliation lawsuits. Sometimes that is really the reason. Sometimes it's not. If, on the other hand, the employer has and tells the employee the legitimate, lawful reason, such as you failed to meet your quota or your reports lacks the analysis needed after giving the employee feedback and time to improve, in many cases the employee will understand this is not the right job for them.
Sometimes managers don’t give a reason because they don't want to debate the employee in a termination meeting or because they don’t have a lawful reason. So, they simply tell the employee “It’s not working out” or some ambiguous variation on that. I represent employees and employers. Any time I hear that as a reason, I am always suspicious regardless of which side I am on. Why? Because it is often a cover for something else, which is sometimes unlawful and sometimes simply bad management.
A good HR manager or employment attorney will talk to the decision maker who wants to terminate and ask enough questions to find out what is really going on. Asking questions such as did the employee recently ask for an accommodation, complain about or question pay practices or other unlawful conduct, return from a leave of absence due to a medical issue or pregnancy, or is the employee the only employee in that protected class (age, gender, race, etc.) can reveal that the manager really doesn't have a legitimate business reason to terminate but is covering up an unlawful reason. Or it might mean that there really is a legitimate reason, but the timing alone makes it look questionable because the manager never talked to the employee about whatever problem is really going on.
If there is a performance reason, doesn’t it make more sense to discuss it with the employee and give the employee time to address it rather than terminate? Or if there is simply a personality clash between the employee and the manager, shouldn’t there be a discussion about transferring the employee to a manager with a different management style rather than terminating the employee.
Simply saying "it's not working" out doesn't end well for anyone.