Here are a couple of sources that point to risks that arise from PUFA intake higher than 10% total energy:
Other studies (some of them actually designed to confirm the older conventional wisdom that saturated fat was bad and replacing with PUFA would help) point to the heightened risk of oxidative stress arising from excessive PUFA intake:
Long story short, there has been a long, drawn-out process of empirically overturning the former conventional wisdom about dietary fats (and saturated fats in particular) from decades past. The material you linked to above is emblematic of a somewhat older variant of the conventional wisdom (i.e., that saturated fat is bad, and that replacing with “heart healthy” PUFA will help). More recently, this conventional wisdom has shifted toward the view that monounsaturated fat is the “good” fat (still shunning saturated fat and de-emphasizing PUFA somewhat).
The alternative hypothesis – which I think is better supported by the evidence – is that saturated fatty acids are “good.” They’re actually a safer form of energy that is less prone to oxidative stress due to their molecular structures. PUFA are rather more risky for the opposite reason – they’re especially prone to oxidative damage. Monounsaturated fats are somewhere in the middle.
And of course this is complicated by the fact that the only two essential fatty acids (omega-3 and omega-6) happen to be PUFA.
All of this is probably going overboard in terms of detail. In my view, the single most important thing is to make sure your sources of dietary PUFA – no matter how much they add up to – are derived from fresh sources and handled / stored in a manner that minimizes oxidative stress.
If you’re doing that, and if you are getting the bulk of your lipids from a (primarily monounsaturated) source like extra virgin olive oil, then I’d say you’re in good shape whether the amount of PUFA represents 10% or 25% of total energy.
Also, there is a fair bit of research that suggests the ratio of omega-6 to omega-3 is probably more important than the total amount you consume. A very high ratio is harmful (the standard American diet can be 15+), and the ideal range is thought to be between 2.3:1 and 1:1.