It sounds like the idea was that the male team hadn't been able to play much, so someone thought it would be nice to invite them to play in the girls tournament, and the exposure might get more boys involved in netball.
That could have been handled much better by having the game be an exhibition, or dividing the boys team as an exhibition game, or something along those lines. They could have mixed the teams and had the mixed teams play an exhibition.
I tend to think the players shouldn't have been shouted at. They are young men but this wasn't their idea and the the adults are the ones responsible to make sure things were fair and safe.