I saw this happen once.
I think it's very disrespectful, and the person who did it has a long history of doing things which to me look ugly or out of place.
I think what happened was that he made the opponent nervous and the opponent eventually lost the match.
but really they were very even and the matches between them were always 3-2 and similar.
This is typical of super expressive people who can never shut up.
so first he began cursing himself and making all this theater, like he always does.
then as it was not enough he began choing opponent's points which supressed the expression of the other guy and made him uncomfortable.
I think it's good to know when it's time to lose and let other people shine