This is narcissistic logic. When people are angry at you, and attacking you - and they do not have a clinical mood or personality disorder - you must accept that there may be a reason behind it. Things said in the heat of the moment are not always fair or measured, but they are rarely meaningless. When you decide that nothing someone is saying is valid because they are hurt, you will probably just invalidate and hurt them further."
I understand your point but I think there's actually merit to that part. Sometimes people are just mad for no reason. My mother would release her frustrations on me when I was a child whenever things weren't going well in a marriage, and I don't think whatever I did deserved that.
There is a good point in saying that there's sometime a real greviance let out in a bad form but sometimes there is nothing to this and nothing you can do or say to change their mind.