...Er...or the father? 'Man the protector'? It isn't just one of the couple's responsibility. But...people leave their babies sleeping unattended in rooms all the time (unless they are willing to drive themselves utterly mad) so that by itself doesn't seem criminally irresponsible...
The problem is that these dogs are bred to guard/attack even more than most dogs - and there were two of them, which brings out more instincts - and in this case, given that these people were attacked themselves the next day they probably knew that they were under threat, so got the dogs as guard/intimidation dogs rather than as pets.
D.