If you have no defects and owe no karma, then you would not experience extreme suffering like that. Those who experience it have defects and karma related to such experiences. For instance, in cases of violence, the recipient is experiencing what they previously inflicted upon others, often even the one who is abusing them was previously their victim: the tables have simply turned. That is why their are cycles of violence and abuse, often bound in a family, culture, city, or country.
This is why it is vital that we work daily on eliminating our defects and karmic debts.
“Nothing is easier than self-deceit. For what each man wishes, that he also believes.” —Demosthenes
"Do not worry; cultivate the habit of being happy." —Samael Aun Weor