But I thought the US had a liberal attitude to air traffic rights ?

Also I find that it's easier for foreign carriers to obtain traffic rights into and out of secondary cities which are poorly served by the national airline.

I don't think LH has a single long-haul service from HAM even though it's a wealthy city. HAM believes that LH treats it as a poor relation (in terms of long-haul services) compared to FRA and MUC.