An IPO (Initial Public Offering) refers to the moment that an equity is offered to the public for purchase. An IPO does not have to be a grand event. It does not even have to take place on an exchange.

The SEC could declare the HIVE Hardfork to be an ICO because that was the moment that HIVE was available to start trading online.

The very fact that STEEM and HIVE are available to trade means that they started traded at some point.

The SEC suit describes RIPPLE as a "unregistered, ongoing digital asset securities offering." The manner in which RIPPLE hit the market does not appear to be the primary focus of the SEC's case. The SEC's ire is raised by the fact that the equity is traded publicly.

The case for HIVE is hinging on the idea that HIVE is a utility token running on an independent blockchain.