Was there any bad ideas presented in the book?
That's a good question, and it really depends on your perspective! On the whole, Jane Addams is celebrated as a social reformer who fought for the rights of the poor and the marginalized with unprecedented success in a very difficult time. A suffragette and a leader among the Progressive Party, she played a role in founding the NAACP and the ACLU, as well as her own project, the Hull House. For her work she was the first woman to be awarded the Nobel Peace Prize.
It's a little hard to disagree with the convictions that led Jane Addams to found the Hull House, a sanctuary and source of community for many who had nowhere else to turn. As Jean Elshtain writes in Jane Addams and the Dream of American Democracy,
"If you were a resident, it would not be at all unusual to move over the course of a day from reading George Eliot, to debating Karl Marx, to washing newborns, to readying the dead for burial, to nursing the sick, to minding the children." (qtd. in "The Nancy Grace of Her Time?")
But, like all good reforms, Jane Addams did face controversy and opposition in her lifetime, and it's there you might look for "bad ideas" (though again, it all depends on your values and opinions). Addams became a "radical pacifist" in the years before and during WWI, alienating both conservative and liberal friends and coworkers. This was an unusual departure for a woman who usually worked hard to find and take the middle ground, effecting the best "possible" good under the circumstances.
Occasionally her determination to stick to the "middle ground," too, cost her the support of those around her, as when she was appointed to the Chicago School Board. There, she alienated her fellow reformers when she advocated compromise against their better judgement on the issue of political influence as a factor in teacher promotions. The reformers lost their positions and Addams refused to step down in protest.
It's not clear that any of these decisions were bad ones—but they were among the more difficult and controversial choices she made, and perhaps a place to start thinking about your own views.