So why did SEC now accepts that everything apart from Bitcoin is a security?
Because they can have control over any crypto if they choose to, apart from Bitcoin. They fear what they can't control. All the other crypto and exchanges are centralized sh*t. They will always favor the one they can control. No surprise there.
Whatever they do or say to bring down Bitcoin, remember 1 Bitcoin = 1 Bitcoin. These are the people who will be craving later on to legalize Bitcoin. No doubt about that.
I highly agree, altcoins that have an active developer have access on the code and they can do whatever they wanted and the government can pressure them to do what they wanted these developers to do. One good example is creating new coins and implementing a swap, and those who failed to swap will have their unswapped coins useless because the developer decided to. With Bitcoin, there may be hardforks but your Bitcoin is intact, and no need to move when hard fork happens.