A bus driver who killed four people while checking his email while driving was given a suspended sentence... Why? = South Korea

A South Korean bus driver in his 50s who crashed his bus into a car in front of him after looking at his cell phone while driving, killing four people, has been given a suspended prison sentence.
On the 2nd, the Cheongju District Court in North Chungcheong Province announced that the defendant, who was indicted on charges of violating the Special Act on Traffic Accident Handling (causing death),
The defendant A (59 years old) was sentenced to three years in prison with five years of probation. In October last year, the defendant A was driving a highway bus inside a tunnel on the expressway in Boeun County, North Chungcheong Province when he struck a vehicle in front of him.
The bus collided with a 15-seater car that was moving slowly in the opposite direction, killing four of the 11 people in the car in front.
The 11 people were elementary school classmates in their 50s and 60s who were about to retire and were enjoying themselves outdoors on the weekend when the accident occurred.
According to the police investigation, Defendant A stated, "The accident occurred while I was briefly looking at my cell phone to check my email."
The Cheongju District Court said, "The defendant caused a serious accident that resulted in the deaths of four people by violating his duty to keep his eyes on the road ahead."
He explained the reason for the sentence by saying, "We took into consideration the fact that he confessed and reached a settlement with all of the victims' families."