Which is why we should work towards a strong European army rather than strong national armies as the earlier comment said. A strong German army will not be at the center of it.

Also Germanies post WW2 military is riddled with wasting money, inefficiencies, ineptitude, subversion by far right extremists…

Germany has no basis to belief it would do military better than its neighbors. So any historical argument will have to deal with the fact that a strong German army historically was always about invading its neighbors. This also does not hold true for strong armies of countries like the Netherland that historically did not invade neighbors so much, but rather took control over trade routes and colonies. That isn’t better, but it is not a historic threat to other European countries. For Germany as a rule of thumb you can say that strong army = invading Poland soon.

With the ever stronger rise of the fascists in Germany and other European countries, often financed by Russia and with the goal to undermine unity inside the EU it is also something to consider. If the EU should fall apart for any reason a strong German army will be a threat to everyone around them, in particular Poland.

It is therefore crucial both as a lesson from history and in looking at the current political developments to build an EU army that is not just some national armies loosely put together.

I think he means that Germany is a very recent country and nation (way more than the US) and was built by one of the nations it now encompasses (Prussia) invading the others under Bismarck. Before that, like Italy, what we call Germany was a mixed bag of principalities, kingdoms and free cities. The problem ,once unified, is that they kept advancing with that mindset, even when the area was no longer German compatible but German similar (Alsace, Lorraine, eastern Belgium, western Poland, Austria…) and got kicked back regularly.

A army’s value is its deterrence. Not its capacity to invade the country’s neighbours (or else, the US would have a much smaller one and spend less of its debt money into it, its neighbours being Canada and Mexico). Deterrence is what keeps the peace to pursue diplomatic and commercial actions with other countries, invasive action brings such a load of costs that even the most powerful armies have to abandon those conquests sooner or later.