How could a non-drinker get cirrhosis of the liver?

There are a number of diseases that can cause cirrhosis of the liver including but not limited to:
Hepatitis C
Fatty Liver
Alcohol Abuse
Blockage of the Bile Duct
Heart Failure causing fluid back-up into Liver
Cystic Fibrosis
Glycogen storage diseases
Alpha 1 antitrypsin deficiency
Hemochromatosis

pills anything can do that.

You can get it from
Environmental exposure
or Infections.
either hep B or hep C
or certain things like ameoba infections can cause scarring.

hepatitis

ummm

if they had a bad case of hepatitis at some point in their lives

It's possible to get just about any disorder from causes other than generally known. In this case the toxic agent(s) is simply something other than alcohol.

It is not always an alcoholic's disease. genetics can play a factor in it too. That is like saying all people who get lung cancer smoke, but they don't.

Not drinking enough water...
Not getting enough air...like not walking for oxygen to keep the blood regenerated.
Not taking enough supplements to help the blood ... (go to your vitamin health-food store and ask them)...some that come to mind are "Lethicin", "Vitamin A", "Brewer's Yeast", and Plain Yogurt (put fresh fruit in it and you'll learn to like it)

BTW , the liver's not the only organ that will suffer if you don't do the above.

over 4 million people in the U.S. have Hep C, and about 85% will get some kind of chronic liver disease including cirrhosis.

it's not nearly as common as ruining your liver by excessive alcohol, but it happens.

two other causes are malnutrition and chronic inflammation.

interestingly enough, people with alcohol related cirrhosis might have few symptoms (or some that develop slowly) while those who acquire it in a different manner have severe symptoms that start very early on.

doesn't sound very fair, does it?

Some drugs can cause this.

While over-drinking the the most common cause of cirrhosis, non-drinkers can get it if they have hepatitis or have a genetic predisposition to it.