Anyone familiar with the Home Planet software, or the Carl Sagan software? Is it possible that either one is in error?

If it's sold over the counter or downloaded from the net, it's likely in error enough to account for this. As noted above, these programs are very difficult to write.

Most of them assume an earth-fixed coordinate system and plot the paths of objects on the celestial sphere by means of harmonic equations. Harmonic equations are the mathematics behind Spirograph. It usually takes hundreds of terms to even closely approximate the true path of the object in the sky, and each of these terms has four coefficients with ten or twelve decimal places in each. Very easy to make a typo.

So, how does this guy think that a dark landing site would have escaped notice for thirty years?

As his rant demonstrates, I don't think he's really thought this through.