Sure he SAID it was an accident, AFTER she reacted with outrage. Then he tried to shut her up. That's the behavior of someone who's gotten away with this behavior before, probably with women who were in a more vulnerable position. She wound up filing for sexual harassment, so this may be the tip of the iceberg for his behavior. It's what she had evidence for.
He said it could happen to anyone, but it could only happen to people who film themselves jacking it at work.
Him using the word "anyone" implies that jacking it at work is so normal to him, that the only mistake he sees here is that he sent it to the wrong person.