A thief justifies theft by deluding themselves, believing that everyone is a thief at heart. Everyone else is just more afraid of being caught/punishment. This is why not everyone is a thief. Given the opportunity, however, a thief believes anyone will steal.

The thief believes they are more bold, Brave, or desperate then others.

This can be applied to many other illegal or immoral activities, Including what this mother is doing. Deluded into believing that everyone is following the narrative and will soon be doing what she is doing. She is more bold than others.