Hillary is a powerful politician and she’s done everything you’re supposed to do as a strong politician. She stridently plays key issues but doesn’t stick her neck out too far. I think she learned that from her push for universal healthcare as first lady. That was a bloodbath and, a lesson that she heeded very well. She has fought fire with fire and built up the infrastructure to become the political tour de force that she is today. The problem is, in doing so, she has become the very thing some would like to see women in politics smash. Hawkish on foreign policy and decidedly vanilla on middle ground issues, Clinton has fought the old “Boys club” by, at times, acting like one herself. That will get her the credentials, the power, and very very likely the nomination but it will also get her some of the ire we’re seeing now. 
The gender guilt angle is weak and she was wise enough to immediately distance herself from it.