Archie was abused by his Father
In the shoebooty episode, Archie reveals to Mike, albeit in a drunken state, that his father hit him and shoved him in a closet for seven hours. It is also revealed that Archie's father taught him to be bigoted. It is a very startling episode, and the reveal comes last. Archie grew up in the house of a violent bigoted man, a man who probably drank too much and was violent when drunk.
I have always wondered the point of this episode, coming so late into the series run. Was it a way to humanize the Archie character, a sort of explanation. Archie came from a different time, than Mike, he came from the depression era, when food was scarce and times were really hard, and if a Father knocked his kid around under the auspices of being strict, nobody cared.
It dawns on Mike that Archie was abused and she kind of begins to realize what is the source of most of Archie's ignorance and backward thinking.
Was the point of this episode, to cast a light on child abuse and its lingering consequences. or was it to soften and humanize the Bunker character. regardless,it did both.
typical of All in the family, with its large audience, it took this opportunity to instruct with a psychological study and the underlying causes of many problems usually begin in childhood, and the effects of parental child abuse. Any person who can lock a child in a closet for seven hours, is the one with the problem. A serious one. It is also important that Archie stopped the cycle of violence and never hit Gloria no matter how much his father tried to knock the humanity out of him. Archie though bigoted was not violent, and had compassion and empathy.