What are some of the reasons behind children and Tantrums / Meltdowns?

Feb 2021
I was told children (defined as kids under the age of 12) that have emotional meltdowns or tantrums are because their emotional needs are being neglected by the parent. I can not find a source on that, has anyone read or have any information regarding that ? I understand some children have ADHD, Anxiety and or Autism which could play into the emotional deregulation; however what about the children who will emotionally fall apart when a parent tells them to turn off a video game or a teacher tells them to sit at their desk to participate in class?

Is it possible the environment at home is producing responses like this in some kids? as in, the turmoil between parents -could- be contributing to ongoing anxiety in them ?