The second point you brought up is false. After the split it will not be possible to spend your coins twice on the same chain. The chains will have effectively split creating two separate currencies, it does not make double spends possible that is just baseless fear mongering.
I never said you could spend "on the same chain" (please don't put words into my mouth - I am not doing so to you).
You would be able to spend your pre-fork coins on both chains so this is not fear mongering but simple *fact* (have you not understood how it works?).
So if such a hard-fork situation arises then no vendor would want to accept any BTC purchases (nor should they) until a clear majority has taken control.
If that control is not taken smoothly and quickly then you would expect chaos.
Fair enough I misread what you said there, was good that I clarified it anyway. I suppose our conceptions of economics disagree on this point then.
We should embrace the concept of Bitcoin being able to split. If you think that this would make Bitcoin lose its value then you should leave now. Even if this blocksize issue does not lead to a split I can guarantee that a split will happen in the future most likely over a different issue. It is this mechanism that actually gives Bitcoin more value in my mind since it ensures the continued freedom and decentralization of the protocol.