The charts don't show anything unusual happening in gold that isn't also happening in stocks. Here is a 5 year chart of gold and the S&P 500. You can see that they have the same return (and yes this is total return including dividends).Gold looks like a bubble and you can't be calm looking at its hockey stick rise.
If we're looking for differences between stocks and gold, the only big difference I see is that they rise and fall at different times, except for the last few months when they have rallied together. The different behaviours of the two are excellent for the PP because it results in lower volatility and a smoother ride.
But I find it funny that people think gold is rising like a crazy bubble, while having no problem with stocks rising to the same degree. And if you do think both are a bubble... then you'll want to hold plenty of bonds. Which is exactly what the PP does, by the way.