On the same blog there’s an article criticising exactly this argument in detail: https://pedestrianobservations.com/2021/06/26/meme-weeding-p...

"Looking forward rather than backward, nothing in Germany’s urban geography is an obstacle to a connected high-speed rail network. With central stations and less of the population living in truly isolated rural and small-city communities, Germany can expect to greatly surpass any other Western intercity rail network if it builds high-speed rail, more than reaching DB’s pre-corona 250 million ridership target."