To clarify for others: random gene mutation within an organism is not the same a random gene introduction from external source.

Take something like an Orchid Praying Mantis. If it were discovered that the Orchid Praying Mantis got some of its coloring from a gene transfer of orchid plants with which it cohabitated, that would remove an enormous amount of random mutations that needed to have occurred within its own genome to achieve that goal.

Nobody is saying that the mantis wouldn't be subject to all of the same forces of natural selection thereafter, or that the particular gene that was transferred wasn't itself a random selection from the orchid. It just makes the arrival at certain gene configurations immeasurably more likely than they would've been within the same time period, given an organism's lineage had only had its own random mutations available.