I suspect: Our high needs in general, including our stronger need for attachment, means that we will have naturally stronger biological drives to ensure these needs are met in order to feel safe and secure. Our neurobiology for self-control is also weakened, so we are more likely to engage in indirect forms of communication to meet them as well as deceiving ourselves, out of survival necessity, that the attachment figure we've chosen is enough for this role, even if they aren't. 

Therefore, we may overlook things that really hurt us and bottle that pain. Sometimes we are able to idealize them to feel that comfort and security we need. Other times, the things we have bottled up, naturally need to be released and express themselves. Pair this all with a dysfunctional frontal cortex, amygdala and other brain regions and you've got splitting behavior. Idealizing for security and lashing out to protect ourselves. 

A brain trying to survive and be safe.