The clarification is just that; a clarification, not a rule change. Yes, the rule differs from the original stance we had on PvP default was first declared almost a year ago, but if anything that first declaration was a rough copy of the default that was open to amendment, and it WAS amended many times. Do you honestly not remember the various changes we've made in all that time since then, or did you just "coincidentally" forget to mention them? The most notable change that led to this one actually occurred when Freya and I entirely rewrote the rules to update and organize the Rules page of the forums, as announced in this thread:
(Finally) Updated Server Rules and Guidelines
MANY rules changed in this thread, and it's not like it was done so subtly. When the update above was made, the very rule we clarified today was written with the intent described in today's announcement, so it is in fact a clarification.
Now, to actually respond to the beef of your post, keep in mind that the clarification was made in the first place because the server was NOT in the perfect harmony regarding combat that you seem to be implying. Had everything been all fine and dandy, there would have been absolutely no need to make the clarification, yet here we stand (or sit, rather). I will not pretend like this version of the rule that was clarified today will solve all of the issues, because it most certainly will not, but I wholeheartedly believe that a fight which the majority favors will more often than not please the most people relative to other alternatives. Assuming people will congregate into settlements and that OOC arguments will become greatly more pronounced than they already are is exactly what it is; an assumption, and a rather extreme one at that.
With that being said, this was (once again) nothing but a clarification, but that doesn't mean that the stating of such sets the rule in stone. The rule is as open to change as it ever was, so if solid issues (AKA real issues rather than mere bickering about what it /might/ cause) begin to arise as a result of it then we can certainly amend it again. However, that comes with actually experiencing the negative side effects you have predicted, rather than simply assuming they will come to pass.
Also, just a passing note. I don't know why people seem to be under the impression that this clarification is a step towards returning to RP default. Putting it simply, it's not, in fact it's not even close to that. The default itself is still stated as PvP, and if most people prefer PvP anyways (including many RP fighters themselves when it comes to mass fights), then it will still dominate RP fighting. I'm not sure why people are already predicting the apocalypse and blowing this out of proportion when literally all we did was prevent a minority from forcing PvP upon a majority.