Not justifying or excusing it, but most people do truly experience a drop in cognitive ability when angry, sometimes to a severe degree. This is easily explained by hormones in their body when amped up, but again, not an excuse.

Part of the fundamental process of growing up is learning to temper these emotions and control them so you don’t lose your reason. Unfortunately many people from abusive environments or simply raised to believe these emotions are justified or right, will instead reinforce it.

Then you wind up with someone who could beat you to death over road rage.

They say they were “just mad” because the reality of “I need therapy to manage my anger issues” is too self-aware, possibly out of reach, and also shameful to admit. That last one is the only one you can affect, and they may still react with anger to the implication they are “irrational” or “not mentally well” or however they choose to phrase it.

Guiding someone to get help with anger management is hard, and most importantly: you should not do it. If someone is violent with you. Get the fuck out. Tell a friend and let them counsel them. Tell their family. But do not stay in a violent situation.