The references seem to try and poke holes into our current understanding of evolution (and I agree it's still very incomplete) and suggest that an alien arrival is the best reasonable explanation to fill the gaps. I'm not sure that's very convincing.

What's even less plausible is an alien visitor, having all the technology necessary to get to earth, somehow needing humans for the purely physical task of extracting metals. I mean we ourselves are now almost capable of automating mining yet haven't made it past our very own moon.