The key here is how someone deals with adversity (like a short stature) inpublic. Yeah he's short, big deal. He had to come back and take a shot at Trump.
My old CEO was a man who I would consider petite. Normally this is used for females, but the man was just of a smaller stature. He was 100% masculine, but probably about 5' 5" and 140 lbs. He was just a small guy. Really nice, really smart. All of his executives were taller than him, women included. He never made a big deal about his stature. Occasionally in the 10ish years I saw him speaking at things he would make a joke about this height but it would be genuinely funny and he wouldn't make the joke at his own expense.
I realize as a billionaire Bloomberg doesn't have to take the high road or come off as likeable, but if you want to be President and you are running against Trump the more you attack, the more Trump will give it right back.