I don't think it's about guilt at all. Guilt is pointless, and doesn't solve anything. Should we all feel personally guilty about horrible things that our fellow gamers have done? If we have not directly participated in or encouraged them in their actions, then no.
It's about acknowledging there is a problem and working to solve it. It's about recognizing that something is causing this kind of toxic environment and considering whether we have contributed to it, and whether there are things we can do to reverse it.
Is it an accident that women account for a very small percentage of the industry, yet are predominantly the targets of threats and harassment? Why does this seem to happen so much in tech and gaming, compared to other communities? Could it be that when people rush to discredit every woman who claims she's being threatened, they're helping create a situation where the abusers, rather than the victims, feel validated and supported by the community? When people choose to talk about Sarkeesian's credibility as a person rather than actually discuss the topics she's discussing, they paint her--not her arguments--as a target to be taken down.
You are not responsible for every violent harasser in gaming, but you are responsible for not making him or her think they are acting with your blessing. That means not participating in the vilification of people whose opinions you disagree with. That means not agreeing with those who would paint gaming as exclusionary and elitist, or acting as a gatekeeper to those who don't pass some narrow criteria for what qualifies as a "true gamer." That means allowing for dialogue and criticism, even if you disagree with it. That means not shooting down women or minorities every time they ask to be recognized by the games they play.