"It's all my fault"

When boys fight, say, between age 5 and 14, fight, they may see that Mom or Dad is displeased with them.  One may attempt a verbal defense of his behavior with an attempt to blame his opponent: "But, Mom, he hit me first."  When girls and young women have a difficulty, instead of trying to blame a different person, they may come out with a statement that a poor or bad situation is "all my fault."  I taught the 5th grade for four years but I never grasped a female reaction of assuming guilt, full guilt.  I first grasped this tendency recently while watching episodes of "Call the Midwife".  When I see a young girl or woman wearing a very negative look and asserting that "it is all my fault", I am sometimes in possession of the whole story, being a complete witness.  My first impulse is to explain, in a lawyer-like way that no, others did this and then that, others bear some or all of the onus of negativity, misbehavior and such.  Now, I just offer a tissue and remain silent. I figure that female processes are in progress.  I think the best thing to do is wait silently and supportively.