POTUS is not a mean spirited person, unless you are mean to him first. He comments about Bloomberg's height. Could Bloomberg have a psychological issue attached to his short stature?
Napoleon Complex
BIBLIOGRAPHY
As a colloquial term used occasionally in psychology, psychiatry, and psychoanalysis, the Napoleon complex refers to a specific type of inferiority complex associated with short people, and especially with short men. It is also sometimes called the “Napoleon syndrome” or the “short-man complex.” Individuals with this disposition are claimed to overcompensate for their short stature by being excessively belligerent, hostile, or quarrelsome in their interpersonal relationships. A fictional example is depicted in John Steinbeck’s Of Mice and Men : The character Curley was a “shorty” who always felt obliged to prove his worth by picking fights with bigger men. However, the Napoleon complex is said to motivate other forms of behavior besides interpersonal violence and aggression. Most innocuously, a short male might make himself feel taller by placing home wall hangings a little lower than normal. Or he might wear shoes with slightly thicker heels.
https://www.encyclopedia.com/social-sciences/applied-and-social-sciences-magazines/napoleon-complex