Decentralized ledger, 21million coins, 10 minute transactions. Any other core values?
What matters are the consensus rules. To be Bitcoin, you must use the exact same consensus rules. XT, Classic, and BU do not use the exact some consensus rules. They have different consensus rules for a hard fork when certain bits in the version are set and a certain threshold is reached. Those are not the exact same consensus rules as defined by the reference implementation, thus they are an altcoin. It does not matter that they are compatible with Bitcoin, they are, by definition, not Bitcoin.
A fork is to allow users to choose and reach consensus. That's why bitcoin is decentralized. So that not 1 group of people has full control over bitcoin.
If you only allow 1 client the spotlight, many people won't even know they have a choice.
It's easy to claim you have consensus when you are censoring all competition. But I'm sure if other clients were given equal chance, the consensus would shift towards one of them.
We need to be fair to the users, and let them know they have a choice. And provide them the tools they need to make their voice heard. Only then we can truly claim to be decentralized.