OMG, I too have encountered a racist, white, old lady while riding the bus. I clicked on your article to see if she was the same one. Alas, she is not.
Being white myself, the racist old lady assumed I too was racist, and said some pretty fucking awful things to me about black people. I was horrified.
It was absolutely repulsive, I won't repeat what she said because, I just can't even. She wouldn't stop talking, and I couldn't even get a word in to tell her to shut up. I just kept backing up from her while she got closer. I was afraid she'd freak out and do something crazy. I can't imagine how much worse it would have been if I had been black, but I'm sure it would not have been safe.
I'm so sorry you had to endure this. Thanks for posting it, your experiences offer valuable perspectives.