Pretty misleading headline. I was expecting to read about hundreds of Canadia kids currently being held in detention. The numbers are relatively small. 
The detentions, while not perhaps optimum,  seem to be reasonable based on the circumstances,  although as the report suggests, kids should not be separated from their parents except in exceptional cases such as if the parent is suspected of being a terrorist. Otherwise do you you throw them out into the street? Foster care? 
I didn't see any alternative suggestions offered by the agency other than not to detain mothers with children which may be a better solution, but is it always possible?