Thanks for the informative reply. I wasn't aware that other Bitcoins were altcoins. Call me an idiot if you will, but would you be so kind as to point out here -
https://coinmarketcap.com/all/views/all/ - which coins are Bitcoin altcoins so that I can see their respective exchange rates?
XT and Core aren't altcoins like DOGE and LTC, however they still fall under the same definition. XT and Unlimited use different rules to Core which would eventually make one incompatible with the other, therefore they are alternate versions that couldn't work together - alt coins.
Didn't the creator of Bitcointalk create Bitcoin. Then yeah, it makes sense for them to promote the latest version of Bitcoin, since they are promoting their own work.
While Satoshi did make Bitcointalk, that isn't the case currently. theymos is currently the main admin, and since it is a private forum, the version of Bitcoin that he wants to promote will be promoted. Any versions that he doesn't want to promote, he won't.