The people who most influence gamergate, the people who gamergate listen to. They do exist. Gamergate may be decentralised, but like any campaign, it does have leaders.

I'm clearly asking for some names. You're avoiding the question. who are the "leaders of the movement"?

Well, one example would be Milo Yiannopoulos. A journalist with a murky past (screwing over staff working under him) and who, prior to joining gamergate, actively mocked video gamers.

Could you identify a call-to-action that Milo Yiannopoulos initiated, or any other manifestation of his leadership of GamerGate supporters? Has he started a campaign? Has he organized an event?

Milo is a journalist, not a leader.

Interesting - I hadn't heard of him. The wiki page certainly seems to back up the claim regarding his contempt for gamers.