I could not help myself

"I...I...I could not help myself!" Please imagine your worst, trite, prejudiced, stereotyped vision of a southern, gun-toten', in-bred red-neck. Take a moment and savour it.
This was my first run in, that I can remember, with this assertion. I was watching Jerry Springer with my family (I did not have any control over the remote in those days) and we were engrossed in the car crash scenario of sub-humanity that was Mr Springer's dish du jour. The utterer was trying to explain why he had cheated on his wife with at least four members of their family, most probably ranging from domestic pets to 70 year old grandmamas-the facts slip my mind.
My father and my uncle found his words hilarious and it became a motif within family discourse for several months after that. It was used to excuse anything from random occurrences to downright unjustifiable behaviour.
"Why did you finish the last of the milk and not consider it necessary to buy anymore?"
"Why did you think it would be a good idea to simultaneously pass wind while scratching your balls in polite company?"
Eventually this refrain was designated to the graveyard of family sayings, overtaken by new and clearly even more amusing cliches.
I was reminded of this phrase when I was reading Nineteen Eighty-Four. The protagonist, Winston, looks back at his childhood self and tries to make sense of stealing chocolate from his dying sister's hands. Adult eyes return to judge supposedly innocent actions. "I could not help myself" did not ease his guilt but it did strike me how entirely overused these simplistically convenient words are.
What do they actually mean? Linguistically there are two problematic aspects to this statement. Firstly, the negative twist on the modal verb suggests a certainty that I am not comfortable with. It implies an inevitability within the situation; the speaker is claiming that there is no other course of action. Whoever gave it to us, we do have freewill. We are never bound to one course of action, regardless of how much we salivate over the possibility of blaming a predestined fate for our woes.
Secondly this help that is spoken of is fidgetingly ambiguous. Why can't we help ourselves? When we try to apply this anti-logic to situations, isn't it actually the case that we have done just that? Helped ourselves to our own desires, selfishly given in to our baser qualities that we try not to admit to during the 99% of our lives when we attempt to maintain a superficial veneer of being an acceptable human being.
Therefore when these words stumble into the public domain, are we actually arguing that we care too little about ourselves or others to have considered a more difficult or arduous course of action? Did we just shut our eyes, take a gulp and think, fuck it, I'll sort out the flack when I need to?
Given the inadequacy of this justification for behaviour that is clearly not corpus mentus, why does it still remain one of the most overused explanations? Sorry if I've burst some bubbles. I could not help myself.