You don't care about my position, and I don't care about yours. It would seem we are at an impasse.
Her posting on Twitter was not for the people in the audience, it was for the PyCon coordinators.
Nobody probably should have lost their job over this, I'll be sure I never apply at either of those companies.
I was a tech evangelist once, and a student attempted to get me fired for me suggesting, on Usenet, that they do their own homework instead of asking us to do it for them. Not exactly the same thing as this in severity or exposure, but still the same sort of general idea. In my case my company stood behind me over the issue, and I started posting things that were not strictly related to my job via another account.
You are ascribing motivations to her that she did not necessarily have. I have seen nothing that indicates her goal was to shame anyone. Did she handle it poorly? Yes. Should she have sent the image privately if she had to? Yes. Was it enough for her to specify the talk and the general location for the coordinators to find the offenders? Yes.
Had she taken option #2 above the coordinators would have likely contacted the employer to inform them of the action they took and the reason behind it. The employer may have still fired the individual over it. Had that happened, and he had posted what he did, and she had posted what she did, sans picture of him, would the same thing have happened? I suspect it would have to a lesser degree. My feeling, based on everything I have read, is that people are, at the core, upset that she was offended by the jokes, and that she should not have been because boys are boys. Her point, rightfully so, is that those types of jokes do not belong in the workplace. Given the number of years she has probably had to put up with that sort of thing I see this as the straw that broke the camels back.
Did she overreact by posting the picture publicly? Absolutely. Was she wrong to react to it? Absolutely not. Were the people telling jokes wrong to tell them? Absolutely, in that such jokes do not belong in the workplace, ad the conference was an extension of the workplace. Should he have been fired over it? Depends, would the company have fired him for saying the same joke at work?