These experiences make you tougher - in adult life, you will run into toxic bosses, colleagues, brutal job interviewers...
It is important to have a loving family and/or supportive friends who can provide a different point of reference.
It's justification for being an asshole to people under the guise of 'helping' them. The people who end up believing it are rubes who do the same to others. Making someone tougher is survivorship bias by another name. It fails to account for the people who don't have supportive family members and friends. It's solution to this is saying, "it sucks, but they just couldn't take it," which does nothing to make things even slightly better for the next person. We're left with those who survived.
Toxic bosses, colleagues, brutal job interviewers are no where near as violent or persistent or inescapable as childhood bullies and if those toxic people did half the things kids do to each other they'd be quickly arrested and thrown behind bars.