  A recent arXiv manuscript, arXiv:1801.03278, claims that a cosmic background
radiation with a black body temperature of $T_{\rm BB}$ ~ 500 K (440 F) was
just barely visible to human eyes, thus fixing the onset of the Dark Ages at
about 5 million years post recombination. This claim presents an insurmountable
biophysical challenge, since even hotter bodies, such as 450 F pizzas, do not
seem to be glowing in the dark. As volunteer referees we show that this claim
is the result of employing an incorrect assumption. Via a corrected analysis we
find that the Dark Ages must have had a significantly earlier start. A second,
more descriptive claim, that a cosmic background radiation with $T_{\rm BB}$ of
1545 K was as blinding to humans as is our own Sun, is based on the same
assumption and may have to be revised.
