So now you are defining an altcoin as any rule changes that cause bifurcations. Though under this definition if Core hypothetically decreased the blocksize causing a split, under this definition Core would then be an altcoin. Even if Core increases the blocksize in the far future this would also then make Bitcoin Core an altcoin. Surely this example proves that your definition is lacking. Unless you are now taking what I think is the correct position that XT is not an altcoin and you can define it as an "altfork" instead, since I can agree with that definition.
I'm not defining it, read the wiki.
I am shocked by you saying this, do you really believe that we should determine what is truth by applying these logical fallacies? I have studied philosophy and politics for most of my life and I can tell you that this is a terrible way to judge truth from falsehood. I urge to study some history and to think for your self.
This is because you don't seem to understand what a fallacy even is. These are unsound arguments for an underlying reality, not something that applies to a subjective definition which is in the process of being settled.