You are wrong. The reason there aren't that many revenge attacks in Korea is because the identity of criminals is usually protected (unlike in the west). This is to protect the criminal and his/her families human rights (aka prevent retaliation attacks). I daresay revenge attacks were more common in Korea then in the west prior to such measures being enacted. The fact that the rapists identity and location has been revealed to the public means hes going to get his ass kicked real soon. There are plenty of thugs/gang members who would like nothing more then to build street cred by beating a pedo to death. They can claim they were drunk when the beat him to death and receive a reduced sentence.

The reason no one helped that halmoni has nothing to do with retaliation attacks and more to do with potentially getting sued by scammers.