You are not accounting for surface area for both countries or population density.
Germany has even higher population density than China (245 vs 137). Of course we have to account for the gobi desert but even so population shouldn't be a factor of comparison.
I agree that the comparison is not fair though, mainly because the infrastructure development between both countries is vastly different, a better infrastructure helps in distributing population over large areas in my opinion.
Since state area alone doesn't produce anything (maybe it's a rough indicator for general access to share of natural resources, but that's not relevant here)
The comparison could be done on province level though.
If you add up Jiangxi and Fujian Province you would end up with roughly the same are and population as Germany with a slightly higher density.
A significant part of China is a desert. Historically the population of China has been clustered along its east coast. That area is not that much bigger than Germany (if at all).
From the exact link you provide, if you remove the desert regions (Tibet, Inner Mongolia..etc..), you end up with 4,403,605 km2 (45.55%) for a population 1,221,000,000 (93.89%) and a density of 277h/km2.
It is still 10 times the size of Germany.
Germany has even higher population density than China (245 vs 137). Of course we have to account for the gobi desert but even so population shouldn't be a factor of comparison.
I agree that the comparison is not fair though, mainly because the infrastructure development between both countries is vastly different, a better infrastructure helps in distributing population over large areas in my opinion.