Why does Lyddie compare the factory looms and Mr. Marsden to the bear in Lyddie?

The bear Lyddie is referring to is the one she faced down with her family in the beginning of the book. The bear enters Lyddie’s cabin through an improperly latched door, looking for food. The entire family is terrified, but Lyddie shows no fear.

Lyddie glared straight into the bear's eyes, daring him to step forward into the cabin. Then when the ladder was silent and she could hear the slight rustling above her as the family settled themselves on the straw mattresses, she backed up to the ladder and, never taking her eyes off the bear, inched her way up to the loft. (Ch. 1) 

For Lyddie, the bear was a turning point. She acted immediately and was able to get everyone to safety, while her mother did nothing. However, her mother decided that the bear was a sign and left with Lyddie's two younger sisters. Lyddie and Charles were able to maintain the farm until their mother told them they were letting it out to pay the debts.

Lyddie resented losing her farm and her family. She felt horrified at how her mother reacted, especially letting out Lyddie and her brother Charles in addition to the land. Lyddie did not enjoy having to work at the tavern. She considered the entire experience insulting and frustrating. Lyddie was independent and intelligent, and wanted to do things on her own.

This partly explains the animal imagery Lyddie uses when she first enters the factory. Lyddie is overwhelmed by the noise and complicated machinery. She has never worked in a factory before, but she is driven to succeed. Still, the actual first experience in the factory is unnerving.

When the machines speed up, Lyddie reminds herself that she has handled worse. She faced down a bear! She brings back this memory to conjure her strength.

She never wasted energy worrying or complaining. It was almost as if they had exchanged natures, as though she had become the machine, perfectly tuned to the roaring, clattering beasts in her care. Think of them as bears she'd tell herself. Great, clumsy bears. You can face down bears. (Ch. 13)

Mr. Marsden is a horrible man. He is the supervisor, but he uses his position to take advantage of the girls under his watch. He makes a move on Lyddie, and later Brigid. After pushing him off, in her fever Lyddie dreams of the bear, and this time she can’t face him down. She fears that she will not be able to overcome this obstacle. However, Lyddie is strong. Although she is fired for attacking Mr. Marsden, she writes a letter to his wife and leaves it with Brigid, so he can never bother her again.