It sounds like they're trying to maintain platform independence while still abstracting platform specific low-level operations. If you utilize machine specific

It sounds like they're trying to maintain platform independence while still abstracting platform specific low-level operations. If you utilize machine specific code in subclasses, how do you generate MSIL that remains independent? If you really needed something like that, could you not use C++/CLI and expose those operations in your own unmanaged library? You will of course lose portability, but that seems like a possible work around.