...you (they) shove it off the plank into the murky and ambiguous seas of "abiogenesis" and claim it's not part of evolution. The very foundation of the theory, the very crux of the argument, and it's "not a part"! By your logic a surgeon couldn't remove a bullet from a patient without knowing the make of gun that fired it.
The word evolution is about change not origin. Change can be studied without regard to origin.