It seems to me the real problem would be the community making a big deal about the fork, not the fork itself. Maybe the fork will take off, in which case anyone who has a position in Bitcoin now will have a position in the forked currency, or it won't, in which case who cares? Sure, Bitcoin might be less valuable for a while while people wait and see how the fork does, but anyone who thinks a hard fork is a large risk to Bitcoin compared to all the other risks it faces is deluding themselves.
I think we would all be better off if the community said, "Fine, fork if you want. May the best fork win," than to sing doom and gloom every time someone decides not to follow the community process. Besides, a bunch of different people being involved does not a decentralized system make. Not if they all have to follow the same process and forks without consensus are not allowed. That can actually be worse in many ways than a benevolent dictatorship, because it will quickly ossify as the community grows larger and more diverse.
If Bitcoin itself had to get community consensus before it was tried, we'd have no Bitcoin. I have no problem at all with someone deciding to fork it. In fact, I *prefer* it, because I think in the long run it makes my own position *more* valuable to have different forks trying different things. Anyone who holds Bitcoin before the fork gets the sum of the values of their account on each fork. Over the long run, the value on most forks will go to zero, but then it's at worst a max function.
Claiming that forks make Bitcoin less valuable sounds to me a lot like Bernie Sanders saying we don't need so many choices of deodorant.