Sensationalized reporting - it grabs readership.
When we were house-hunting in a new town a few years ago I spotted a newspaper headline that blared: "Local Murders Up 100% Last Year." Alarmed, I immediately dropped money into the machine only to learn there had been one murder, 100% more than the previous year when there were none. But the sensational headline sold at least one paper.
1/0 = Inf. If there had been one murder in the previous year and two this year, that would be a 100% increase. I do not think my town has ever had a recorded murder. The town next door, similar in demographics, had its last murder over 25 years ago, when some guy was having an affair with a woman in his church’s choir. When she broke it off, her lover killed her husband.