Regular people will be traumatized. Abusers, narcissists, sociopaths, etc. not so much, they will rationalize it away.
Of course, when such a thing happens, most of society rushes to assure the blamee that "it's not your fault, the only person responsible for a suicide is the person who commits suicide." So, whether through this or through therapy, they will get absolved and shed the trauma quickly or over time.
Some people would feel trauma their whole life long but I don't think it's as many people as one would believe. Suicide as a form of revenge is pretty useless for this reason imo. And this is coming from someone who was determined to do it because of some gruesome bullying at school.