The SEC distinguishes Bitcoin from other cryptocurrencies and considers it to be a decentralized digital cash, exempting it from the classification of "security" that applies to many other tokens.
Bitcoin, due to its decentralized nature, market cap, and lack of involvement by its founder, does not fit the criteria of a security according to them.
I mean, I find funny the "according to them" part: they set those parameters, clearly bitcoin can't fit there, everybody knew that and yet they were somehow fudding giving the impression that maybe bitcoin, at the end, could actually be a security. That's always been impossible, anyway it's nice to finally have a confirmation.