It's a therapy technique.
People who have experienced trauma, for example the thought of HRC being President, may still exhibit trauma-like symptoms even though the trigger of their trauma either isn't real or has been removed (i.e. Donald Trump is actually President, yet thoughts of HRC still cause anxiety, sleeplessness, perseveration, drug dependency, cutting, etc.).
It's sometimes helpful to gently and repeatedly remind a patient that the source of their anxiety/trauma/night terrors doesn't exist, much like you would patiently explain to a toddler that there are no monsters under the bed, in the closet, downstairs with mommy, etc.