Germany is one of the top defense spending countries.
You may check also a map. Germany is surrounded by friends. Germany also doesn't have an empire to maintain.
We have spend billions on useless adventures like in Afghanistan. Luckily Germany was not stupid enough to take part in other adventures: Iraq, Libya, ...
That the US decides to spend as much as the next twenty countries together is only their problem. But the US politics has made parts of the world a very unsafe place. Check the US politics in north-africa and middle east: toppling regimes and trying to install new regimes. This has created a huge mess and creates problems throughout the region. The rise of ISIS/IS is one of those results.
Europe is really suffering now because of the idiocy of American politicians. There are massive waves of migrants fleeing Syria into Europe via boats. Thousands are dying at sea, hundreds of thousands are arriving or being rescued. There is nowhere to put them all. America and its stooges turned these north African countries into anarchy zones and now Europe is paying the price of taking care of the refugees.
Germans are just starting to realize that they are as much a US poodle as the Brits across the pond.