When Jimmie finally makes it back home after fighting with Pete, Mary is fit to be tied—she says that Maggie is a good-for-nothing so-and-so who has compromised her morality and ruined the family's reputation. Mary concludes by describing her daughter as wicked.
Jimmie makes a feeble attempt to defend Maggie, but it's a no go. He attempts to put himself in someone else's shoes… maybe all those women he has dated have brothers? Maybe he's no different from that cad Pete? On second thought: nah.
In fact, Jimmie decides he's so definitely different from Pete that if anyone in the neighborhood brings up Maggie's relationship with the guy, Jimmie will not defend his sister's honor. Ouch.