If Core comes out with a patch for a bigger blocksize will that automatically turn Core into an altcoin? That is just silly reasoning.
Your parallel is flawed. If Core does that there will be no alternative Bitcoin. There will be smooth consensus switch to a patched Bitcoin. Not the case with XT altcoin.
If XT altcoin wins over Bitcoin I'll sell all my bitcoins because that will prove Bitcoin can be forked by a very small group of people in whatever way they want! I'm sure that even XT supporters will not be happy about that.
If XT wins that means there is widespread consensus that the XT client is better and the way to go forward for Bitcoin. Not supported by a very small group of people like you claim here, the very small group of people will then in fact be the ones supporting Core. Yes, you can be part of a small minority opinion too, and it sucks but that's life!
I'm not really a die-hard XT supporter by the way, but I do support bigger blocks and if the Core developers don't find a way to give Bitcoin room to scale then I think I should look for alternative Bitcoin clients. If it turns out I'm one of the few and part of a small minority, well too bad for me! I won't cry about it like you or call Core an altcoin ruled by dictators with only a small group of supporters behind it.