I think we tend to forget about the importance of reversion to the mean, socially.

We think: Germans are like this, the French are like this, the Dutch are like this... without thinking that, when one moves out of sync w/the others, its likely, statistically, to move back into line w/the others.

This has nothing to do with left or right specifically. It means that, whatever the mean is, if a country is not there, it's likely to move in that direction over time. It's more likely to move closer to that than away from that, measured over years.

The Dutch were very liberal and still are in many ways, but in such a situation, they are more likely to move in the "less" than "more" direction. And this is probably such a case.