Germany already has the money to do that, but it doesn't want to.
Thus, spending money on the military has no relation, as to why other things aren't being done.
Therefore, complaining about those other things, in reference to this thing, is not logical.
They are separate.
Now take a step back. Look at history. Don't be fooled into thinking humans have somehow inexplicably changed in a few decades.
Now, should a country be able to defend itself? Should it prepare?
If not, why?