A good number of the people here are bound to be targeted by the Soul-Devouring Worm.
Some will experience tampered memories while others will suffer intelligence damage, slow thinking or even idiocy. A smaller fraction of them may even live a few or dozens of years as severely ill patients after their memories are altered.
In Lv Zhong's eyes, hardly anyone here was truly good. If they hadn't crossed paths with him, Lv Zhong wouldn't have cared if they were good or evil, black or white. But since they had encountered him and furthermore, had messed with his close friends and even attacked him, Lv Zhong didn't intend to spare them a harsh lesson.
As to whether the punishment was too severe, Lv Zhong couldn't care less.
To Lv Zhong, simply not taking their lives was already considerable restraint on his part. These rich hoodlums had committed plenty of cold-hearted deeds and crimes without facing justice.