The "because reasons" you're attempting to gloss over here is "to make more money." The result of a fork will be much like the creation of an altcoin where funds at the moment of fork are mirrored onto the new chain. From that point onward the economics that govern altcoins takes over. It's called "pool hopping" and it's currently a thing; it isn't some far-fetched pipe dream of mine. Miners/hashers/whatever will change targets to optimize profit per energy unit spent. If there is a large demand for real bitcoin and little demand for USGavincoin, even if 95% 80% 51% (lol why not because democracy!) of the blocks previously declared allegiance to the fork, hashing power will shift from the latter to the former.
Please notice that you last sentence starts with "IF", and that you did not provide a single argument why the chain with 5% of the hashrate, which, even if not actively attacked, would release its first spendable coins 2 weeks after the fork (100*10*20 = 20000 minutes), would have coins that would be more valuable than the coins from the other chain.
You sorta answered your own question there. Since when does
limiting the supply of something lead to a
decrease in its price?
But that's not my answer. My answer is this: because
MPEx will not accept altcoins; especially not those promoted by
CIA muppets. That's
somewhere between 300k and 400k that will be dumped into the USGavincoin market in addition to 3.6k daily.