I agree that 15% may not be that extreme, but 15% is not all that's at stake. 100% of all ether existing has so far lost 20% of its value (relative to other currencies at the time of the article's writing). I wouldn't be surprised if it continued to drop further. This may cause enough panic among miners to actually get a majority to agree to a hard fork.

Edit: for the record, I don't own use Ethereum or own any ether, so I would also hope that a hard fork doesn't happen to bail out a single contract, but I have no financial incentive on the line.