A lot of German students who did their AS Levels ins Britain in their 11 grade without having been before in the UK did very well, thus it is very fair for the ones, who can't be sent off to boarding school, to be treated the same. And you don't need to have 8 A*, just 5A* for Abitur and just 3A* for fachgebundene Hochschulreife, so you can't really complain. I e.g. had 10 traditional subjects plus an extended essay plus 4 examinations over the whole two years without any possibility to retake. I don't complain and enjoyed the education I got, but you should really rethink your argument it would be unfair because A Levels are way harder.
And no you a B in Germany isn't lower than a B in the UK, you are twisting your arguments to your side, denying the possibility to use the same arguments on the other side.
Sorry, I hate these discussion, who has the higher level, but your claims are "ridiculous".