I believe that they didn't really rank the national cuisine, but the food available. In Germany and England you can basically enjoy the cuisine of all countries in the world. Because of the large number of immigrants, of whom many operate restaurants. Plus the number of three Michelin stars restaurants.

I can't speak for the English, but as a German I can tell you that, especially the Southern and Austrian, traditional cuisine is actually really good! Ask tourists (even from the Mediterranean) that went to a good restaurant in Bavaria and ate Schweinebraten mit Knödeln/roast pork with dumplings and red cabbage. The majority will tell you that it's very delicious. Of course there's not simply one dish. I think many people are aware how good our bread and sausages are and the large variety. Germany has over 3,000 types of bread and 1,200 different pastries and rolls, making it a world leader in bread variety. Plus there are over 1,200 to 1,500 different types of sausages in Germany, with regional variations and unique recipes for each kind. This vast variety includes fresh, grilled, cured, smoked, and spreadable options, reflecting how deeply embedded sausages are in German culture. As well as bread is.

The way Mediterraneans are looking down on our cuisine, probably has more to do with our "eating culture". People here just don't put the same effort into food and its preparation. For example, we don't want to spend as much money on having fresh produce and food in general. If you look up how much of their income Italians spend on food vs. Germans, you can see a fairly big difference.

Regarding British food: On the internet we usually get to see these abnormalities like deep fried Mars bars or chip butties. I also don't know how one could come up with such weird food. But I'm pretty positive that it's not the daily diet of most British people.