Antifa is not one organization, that's ridiculous. It would be like claiming that "Anarchists" are a terrorist organization.

You link to that press release like it means something more than changing a lake's name by fiat.

Antifa isn't an organisation at all. It's a loosely defined ideology / set of tactics that leftist movements (everything from black block kids to local democratically organised spaces) sometimes use or follow.

Antifa is as much of an organization as Anonymous.

The United States classified Nelson Mandela a terrorist until 2008.

Yeah, yeah, soon any opposition to Trump or Israel is deemed terrorist...