The slam dunk answer, provided in the comments, by SM:
Mrs Shear... was allowed to sit wherever she wanted by law. She was allowed to sit wherever she wanted by the Bus Company. She was allowed to sit wherever she wanted by her Rabbi.
On to the bus come some people who decide that they will impose their will on other people, knowing that they are not permitted to do so by the law of the land. They also know that they can, if they wish, make this particular bus separate seating if they go about it the right way. They have chosen not to do so.
What do we call someone who treats another's property as their own? We call them a thief.
Now, these people who ask Mrs Shear to do something. There is no problem with the asking. Mrs Shear can say either yes or no. If she MUST say yes then she is not being asked a question. She is being given an order. An order can only be given by the people who are entitled to do it - not the people on the bus.
So there can be no judgment on Mrs Shear because she says no. Bear in mind that there is no halachic issue here, unless it is halacha that because these Charedim insist you do this you must do it. No Rav of these people have forbidden them to travel on a bus with mixed seating because we must presume that otherwise they would NOT have travelled on that bus.
So, not only are these people presuming to give orders to someone they cannot order about. Not only are they behaving like the owner of the bus. They are also purporting to give an halachic ruling when they are not qualified to do so. Otherwise when Mrs Shear says no that is the end. That also applies to women who shout and drag other women about.
Ed, you seem to think that these are the people to whom Mrs Shear should have said yes. But actually, what are our halachic obligation confronted with a thief? With someone who pretends to be an halachic authority and rules when they have no right to do so? With someone who bullies others?
Now there is then a physical attack which we can all agree violates halacha. That the other people on the bus fail to intervene merely indicates that they are predisposed to misjudge the situation and favour the man.
But Mrs Shear then starts to tell people what happened and they do not listen. Worse, they assist the offender to escape. What is the halachic position about someone who knowingly assists a criminal?
So it seems to me that, properly analysed, Mrs Shear behaved entirely appropriately. When Ed complains that she was 50% to blame he is wrong. His mistake lies in attributing to Mrs Shear a DUTY to comply with a request. But there is no such duty. She was free to say yes or no and she is under no obligation to dishonour herself either by obeying an unlawful order or by accepting a position she finds demeaning.
Ed has only looked at this from the man's perspective and has assumed either that the woman must do what she is told, or that what she was asked to do was neutral. There is absolutely no basis for either supposition and he has not enquired. He is therefore in the position of a Judge who favours one side, about whom the halacha says he should not sit in judgment.
When it comes to publicising the matter, it seems to me that Mrs Shear has sought to avoid three things. Firstly, that the criminal who assaulted her should assault anyone else. Secondly, that the men who could have prevented what happened (a Torah Mitzvah) must know that they judged the situation wrongly so that they do not make the same mistake again. Thirdly, that the community does not deny what has happened.
Again, Ed's mistake is to assume that all Mrs Shear wanted to do was make trouble. Again there is no evidence of this. Particularly, Mrs Shear herself makes it clear that she dis not encourage anyone to sit where she sat. Her behaviour is thus to be contrasted with the behaviour of those who tried to prevent her doing so.
When one looks at what Ed says, this casual, untested and unproved assumption lies at the root of everything. So, because Ed cannot or will not think positively of a fellow Jew (another mitzva) he calls on someone to "defend" Mrs Shear. That in itself is an error because Mrs Shear requires no defence. The assumption that she does is because Ed has already taken a fixed view.
I do not entertain any hope that Ed is persuaded by this analysis. Rather, it is necessary to give it so that he cannot say he publicly asked and no one responded.