Here, Gentry tries to take the issue of reporting extragalactic redshifts as velocities vs. z and expand it into a controversy. Historically, astronomical Doppler shifts of stars were reported as velocities. This was true for the spiral nebulae as well, long before their extragalactic nature was known and before the discovery of the Hubble expansion. As the nature of the extragalactic redshifts became more evident and confusion over which redshift to speed convention to use intensified (non-relativistic vs. relativistic), it became obvious that the best solution was to report the redshift parameter, z, since it is tied more directly to observation and is model-independent. This is the solution used in most modern extragalactic catalogs.
It is notable that Gentry's references for this claim are not current research papers, but cosmology textbooks which cover the history of the field. If it were an active controversy, there would be plenty of recent references available, but the fact is this alledged controversy is actually an historical note. If I wanted to claim the extraterrestrial origin of meteors was controversial, I'd cite textbooks on the subject, perhaps also noting their terrestrial origin is related to the fact their name shares the same root as meteorology(!)
As part of this paper, Gentry computes the gravitational force between two large clusters of galaxies and compares it to the force holding the Sun to the center of our Milky Way galaxy. He then claims that the huge value of the cluster-cluster force compared with the galaxy-Sun force is a problem for structure formation after the Big Bang. While he makes no mathematical errors, he commits a huge conceptual blunder. What a shame he didn't examine self-gravitating systems much closer to Earth which would have made the error more obvious before he embarrassed himself in publication. Here is a problem accessible for analysis using an N-body gravitational simulator (see Science Tools).
Compute the gravitational force that the Earth and Moon exert on each other. Compare that force to the gravitational force between two pebbles (say 1 gram each, 1 centimeter apart) on or below the surface of the Earth. Is this a problem for the Earth staying together gravitationally? Even if you include non-gravitational (electrical/chemical) forces between the pebbles, it is still far smaller than the Earth-Moon force. For even more entertainment, compare the force the Earth exerts on the Moon to the force the Sun exerts on the Moon. Is the Moon gravitationally bound to the Earth? Hint: what is the actual net force of the Moon on the two pebbles? What is the actual net force of the galaxy cluster on the center of the Milky Way? On the Sun? Remember: Force is a vector.This is a Physics 101 problem and Gentry got it WRONG!