Because EU and German jurisprudence have created plenty of holes. It used to be that pure software inventions were unpatentable, while mixed software/hardware inventions (the classical example is anti-lock brakes) were patentable. Doctrine was that the invention had to have a "technical effect", basically working through the forces of nature. So, an invention was patentable originally if the novel part of the invention extended to the hardware.

But that principle was weakened over time, first by saying that the novel part of the invention did not have to extend to the hardware, just that any novel part in the software had to also be inextricably linked to the hardware, even if there was nothing novel in the hardware portion. That was not per se unreasonable, but then opened the gate for further exceptions.

Exceptions were created for software that e.g.:

- did calculations on a computer that were then manually used to configure hardware, e.g. calculations for how to adjust diving equipment, even if the computer had no physical connection to the equipment. - low-level system software, such as page buffers, even if it was abstracted over the actual hardware. - Programs that tested the validity of chip layouts.

Basically, whenever something could related to hardware, however indirectly (even in a roundabout way, e.g. through energy or memory savings), even if the novelty was unrelated to the hardware, courts were likely to find a way to rule that the software is patentable.