> it has no "viral effect" in case of linking
The short answer is that there are certain protections that ensure interoperability, and that linking to software does not make it a derivative work.
That directive is usually understood to be about reverse engineering in order to build compatible software: "to obtain the necessary information to achieve the interoperability of an independently created program with other programs" being a key bit.
It's not immediately clear to me - a programmer but not a lawyer - that this has any bearing on whether linking creates a derivative work.
Have any other experts, or courts, weighed in on whether this analysis is sound?