German law....

What's that law?

All EU driving licenses (no matter where obtained) are valid for use in Germany. There was no change in that respect in Jan. 2013.
If you stay in Germany longer than 6 months, you need to change to a German license. Maybe you failed to do that?
Otherwise, please explain what the whole issue is about. I really cannot find or imagine anything here.

So you are complaining that you cannot convert your Lebanese driving license to a German one.
Since driving license conversion rules are usually reciprocal, this is probably the case because Lebanon does not accept conversion of German licenses, or because the driving standards there are so low that letting Lebanese license holders drive in Germany is seen as too dangerous. I don't think that is stupid.
In any case, if you can actually drive, what is the big difficulty in doing the test and getting a German license? Doing so will help you more than ranting on a public forum.