Why only have the link to bitcoin core at the top, and not classic, unlimited and XT as well?
It's easy to remain the client used by most users if you control the main platform of communication, but this is not decentralized at all.
Bitcoin Knots (
https://bitcoinknots.org) for example is listed on Bitcoin.org while others aren't because XT , classic ,unlimited etc... do changes to the network rules which makes them an Altcoin , as simple as that.
None of them violate the core values of bitcoin.
Decentralized ledger, 21million coins, 10 minute transactions. Any other core values?
The only one violating the core value of decentralization is Core, because they are actively trying to manipulate many platforms in order to gain control, and thereby centralizing bitcoin.
If you truly want decentralization create your own forum. By putting all coins in one forum is centralization.
There are multiple forums, but like many things, the power of the forum is the network. Core somehow managed to get hold of the main communication platforms (this forum and /r/bitcoin) and is leveragng that control to centralize bitcoin and act like the only 'legitimate' developers. Thus, centralization is happening.
Technically, until a Bitcoin fork obtains consensus, it is an alt chain.
All chains should have a fair chance as long as they don't violate bitcoins core values. One of the most important values is decentralization. Core is threatening this core value.
No one is stopping any one else from choosing a different version of Bitcoin to use, especially not the forum.
No but they are using the power of propaganda to make Core seem like the only 'official' client. There are other clients out there that are just as 'official' and legitimate. And arguable healthier for bitcoins longterm
survival.
If I made a coin named 'Bitcoin 2', and used almost all of the exact same properties of Bitcoin (21,000,000 coins, 12.5BTC/block, same chain) apart from changed some technical aspects (block size, block speed etc) would that be an 'official' version of Bitcoin? If not, why?
As long as it's seeded from the genesis block, and if it reverts any already existing transactions the rules for it need to be consistent with itself. (And I am sure you'd need good reasons to do so, or else you wouldn't get support).