Re: Good
I think something along those lines is written into the Japanese Constitution, not sure it's an international treaty. Also, not sure that there is anything like that in the German Constitution.
The German Army at the tail end of the Cold War was close to half a million strong, so not exactly small. It's currently I think a bit under 40% that size.
There have also been continuous reports of unserviceable planes, ships, submarines, tanks, etc, since the end of the Cold War (it did end, didn't it?) because the money isn't there to maintain/operate them, provide spares, etc.
2% GDP is an agreed target minimum spend on defence. The rules are quite generous on what counts (pensions to former service personnel do). The German Government agreed to the target, like all NATO governments. It's not entirely unreasonable that countries that do meet the target get upset with the countries that don't seem to be trying.