I am sickened reading the story.
Regardless of whether it was right to deplane the family or not, the whole situation was handled extremely poorly and there can be no excuse for that. Particularly when there were children involved, for whom the whole experience of being evicted from the aircraft would have been frightening and traumatic.
The Captain should have come and explained the situation himself. Emirates should have had their station manager meet the family, arrange for them to be accommodated overnight and assist them onto the flight the following day. This would have turned a horror story into a positive one, as they recount the experience to others. The inconvenience of an overnight stop in Singapore would have paled in comparison to the warm and supportive customer service they would have experienced.
Opportunity missed, EK.