To clarify #1: No I don't think the geeks who are merely "socially awkward" are to blame for abuse at conferences, you have to be extra broken inside to do something like that.
Like much else, it's a continuum, at one end you have "the run of the mill, socially awkward geeks we all know and love" and at the other you have "egotistical, poorly socialized brutes, who cannot tell the difference between a woman talking about a technical issue and flirting".
The atmosphere that allows the socially broken to think that what they are doing is ok is certainly to blame and conference organizers should make sure that they do their part to improve the atmosphere.
To clarify #2: I certainly don't advocate shunning anyone, the best possible solution is to educate and socialize everyone so we can all get along, without any groping or violence.
However, when someone actually go out and violate geekgirls physically, then I'm all for public shaming, because that will at least teach the perpetrator and the community at large a lesson.