"Generally speaking, the primary handgun cartridge choices for deer hunting include the .357 Magnum, .41 Magnum, the .44 Magnum, .45 Long Colt (marginal), and the .454 Casull."
I would say, ignorantly speaking if this author thinks the 45 Colt is marginal compared to the others he listed. What a dolt.
Probably marginal in the sense of being used in a Colt SSA or any of the Colt clones. Not so in a Ruger or Freedom Arms or any of the specialty revolvers design for hot .45 Colt loads.
That would be my take on his comment.