If I am in a conference and I say something funny to the person next to me, and somebody else hears it and tweets it with my photo, well then I am flattered. I made people laugh. If Adria Richards had called out a comment for being funny, rather than sexist, would she have been fired? And how can you define that difference?
All employers over-reacted equally.
And next time a woman at a conference - or a man at a conference - hears a comment he or she thinks falls outside what is acceptable within the given environment (and written conference standards), he or she will be too scared of the consequences to rectify the situation.
Let's hear it for lose-lose situations.