From what I have read, the curfew law does indeed say that you are allowed on your own property (porch, garden, balcony etc) after-hours. And the police were probably either ignorant of this, or tonedeaf to the situation, or just another of the bad cops that seem to be so common.
That said, I dont really see the need for people to contest every instruction given to them by the police. Just do everyone a favour and go inside - you can probably come back out 5 minutes later after they have passed anyway. Still didnt deserve to be shot though, of course.