I think the comparison of rankings is very interesting. Why does everyone on this site feel the old classics are underrated in this ranking more than in any other ranking?
For starters the rankers are different people, europeans; In europe we do not nearly have the same golfing culture like in the UK or US. For years only a very small fraction of the population was into golf. This has only started to change in the last two decades really. Therefore the maintenance of courses for years has not been on a par with that in the UK or US. A fast green in mainland europe would be considered medium in the uk and slow in the US, I'm sure.
Funnily this results in US-style RTJ and discipels target golf courses, mainly built in Southern Europe over the past few decades generally being overrated, because they often do have maintenance budgets and expertise that many club-owned courses do not have. As a result the dozens of Colt, Simpson et others' classics are being underrated or even overlooked.
There is light at the end of the tunnel though. More and more clubs are refining their maintenance practices, often importing expertise from overseas, and also more and more clubs are involved in restoration projects. Many of the old classics have been tempered with over the decades by club committee's. I know this has happened in the US and UK as well, but because of the aforementioned lack of a strong golfing culture the damage has been far greater here.
Good examples that I know of are Haagsche (Tom, you should revisit) and Antwerp, but also Eindhoven in the Netherlands and Belgium. If these restaurations continue, I am sure the old classics will get more and more appreciation and rightly so. Especially if we can look through the fact that green speeds may not be comparable, but then again what were the green speeds in Colt 's and Simpsons days?. (Green speeds I think are also different in Europe due to the fact that environmental legislation in many countries permits much less in terms of maintenance than in the US).
What is fair when comparing the rankings? Obviously the in-depth quality in mainland europe is not comparable to the US or UK. And the world's best courses are certainly not in Europe. But a number of the old classics would certainly not look strange in the 70-100 bracket of the world top 100, especially with restoration programs continuing.
But there is more: Some courses are simply overlooked. Courses talked about across the North Sea or the Atlantic are often the courses near major airports/cities or in popular holiday destinations, however there are many others; Many people have not heard of Rosendael, or Sart-Tilman or Grand-Ducal, but they are much better tracks than half of those in the European top 100 ranking.
I have played 10 of the world's top 100 courses and 32 of the european top 100, which is not enough to pass final judgement of course. I am sure though that many people would be pleasantly surprised when they come over and sample the old classics which are here (as well as some of the local classics by architects like Arana and von Limburger).