The Short Version
This claim is not supported by the evidence. Multiple high-authority sources — including the CDC, NIH-published research, the ICRC, and the UK Victims' Commissioner — document that online pile-ons and mass harassment regularly produce serious real-world consequences: mental health deterioration, suicidal ideation, physical symptoms, impaired daily functioning, and career or reputational damage. While not every pile-on ruins a life, the word "rarely" significantly understates how common these harms are.