> Many terrorist organizations operate with individual cells who work independently, so that they can't implicate each other. I'd still call that an organization.

I'd argue there's a more interesting parallel with political terrorist organizations: they often start out as non-violent groups until subsections radicalize over time, therefore attracting a set of new members who further radicalize the group. Think Hamas, PKK, etc.

It's pointless to argue whether GamerGate was about "ethics in journalism" because there's the set of people who care about that and the set of people who like to threaten women over the internet, and it's not clear which one are "GamerGate" and which ones aren't.