Nothing in this idea ("... humans were transported here ...") would suggest that humans and chimpanzees should have identical cytochrome c molecules, or genes for same that differ by a single silent mutation. In a similar vein, chimpanzees appear to be genetically closer to humans than they do to gorillas or orangutans.
The "transported here" humans are inexplicably similar to a particular "not transported here" ape species, which appears in every genetic way to be our sister species.
I didn't say transported here from a distant galaxy. IF humans were transported here, which is a big if since there are other possibilities as I noted, it was almost certainly from close by. Mars would be one possibility, but there are others. Consider Saturn's little moon Iopeta for instance:
Maybe there's some naturalistic theory as to how a moon gets a wall around it on a great circle arc which can be seen from space, but I've never heard such a theory.
The other possibility would be that they had demokkkrats or palestinians (or evolutionites) or some such there and built a wall to keep them on their own side of it.