Well I wouldn't consider 0.65 high but that's a matter of opinion.
Understand that the "all exchange" P/C has been fairly high as well with respect to its historical range, but it has not been as extreme as the CBOE numbers. As such I think you should be careful with terms such as "unprecedented" when describing the number. The bottom line is that the "all exchange" number which I track and have been tracking for years ecompasses the CBOE trading. But since it takes into account all options trading then it is necessarily more accurate.
I'm not trying to "rationalize" the high CBOE number away. I'm not sure what purpose that would serve. But the amount of chatter the CBOE number has been getting in the financial press as well as on many discussion boards needs some perspective. If you want to continue using the CBOE number than that's your perogative, but overall we are simply not at the extreme levels in put buying that this figure would lead you to believe. Take from that what you will.