Jon Jones is an amazing fighter (And probably he will be the greatest ever in few years), an extremely gifted athlete, someone that is so damn talented and also is lucky enough to have first class trainers.
His amazing talent and his hard work has made him the fighter that he is today.
Unfortunately, as a person, he is still a little kid.
At 26 (or 27?) years old you are not a teenager anymore. You are expected to be an adult and to act like one.
And every true adult knows very well when he must react to an ofense, and when he should simply ignore it.
Jon Jones still gets angry at random insults made by random people in Twitter and backfires with very childish insults of his own.
I am not going to discuss if the "lol that's your girl?" comment was an attack or a humiliation or whatever you want to call it.
The important thing here is that it is one of those comments that you can expect from immature brats, but definitely not from a grown man who happens to be a MMA world champion and a role model for many people.
Just as he proves everytime he fights that he is a fucking machine as martial artist, he proves as well how childish he is everytime he talks.