As I pointed out in the comments to the above video, the whole question is based on a number of fallacies (including considering Bolt Action a historical wargame…).

To begin with, he is comparing apples and oranges: Warhammer 40K is a game, and historical wargaming is a whole category of which WW2 wargaming is a subsection. It would have been different if he compared WH40K and, for instance, Bolt Action. In that case, the starting assumption that the former is much more popular than the latter would have been correct; on the other hand, the belief that most of the people into wargaming are largely playing WH40K is erroneous, albeit quite common amongst WH40K players. Examining the data collected by the most recent (2022) edition of the annual Great Wargaming Survey held by the magazine Wargames Soldiers and Strategy, it turns out that the most popular wargaming period is actually WW2, with WH40K coming fourth, just as it has been in all the other annual surveys in the past five years… and the whole question he has posed crashes and burns right here I would say… It is quite obvious because, as I said, he is comparing discrete entities: WH40K is a single game, while you have several dozens of WW2 systems. If we consider the whole galaxy of historical wargaming across every possible period things would be even worse…

So not only WW2 is actually way more popular than WH40K, it actually turns out that a lot of people play the Germans, it is probably the most common faction for a number of different reasons: first of all, they are like the French in Napoleonic wargaming, someone has to play them if you want to have a game most of the time, so a lot of players that have more than one faction generally have the Germans as one of them (myself included). Many like playing the Germans because they had a lot of interesting kit and equipment and, unfortunately and especially in some countries, there are also some people who play the Germans because they are actual fascists…

So, at the end of the day, the whole question does not hold: WW2 wargaming is actually more popular than WH40K and Germans are probably the single most popular faction in WW2 wargaming…