The definition of hierarchy is a system or organization in which people or groups are ranked one above the other according to status or authority. The definition of trauma is a deeply distressing or disturbing experience. Putting trauma in a hierarchy means assuming that some trauma is worse than others.
Sometimes, people do this with their own trauma because they do not want to accept that something (dare I say) traumatic has happened to them. If a person can say, well, this trauma is not as bad as _____, it may allow the brain to process things differently and not allow these things to weigh so heavily on the person.
There are people who have never experienced trauma who also assume that some trauma is worse than others (and therefore that the impact of some trauma should be greater than others.)
The reality, especially for trauma survivors, is that placing trauma in a hierarchy can suppress the ability to heal as well as invalidate the trauma a person has experienced.
The bottom line? Trauma is trauma. Everyone reacts differently, and there is no trauma that is no more severe than the other. If you have had something tragic happen to you and you had no control over it, you can can have whatever healing that you need. So please, do not compare your trauma to another person’s trauma. And do not force your opinion of trauma on someone else. Everyone's trauma looks different, and everyone will process and heal from trauma in different ways as well.