I disagree with the person's reasoning. In free fall, the force of gravity acts on all objects equally, regardless of their mass. According to the theory of gravity, all objects accelerate towards the Earth at the same rate in a vacuum, which is approximately 9.81 meters per second squared, due to the gravitational pull.
In the case of skydivers, all of them—regardless of their weight—experience the same gravitational acceleration. The difference in the distance between the skydivers in the picture may be due to various factors such as starting position, body orientation (which affects drag), or variations in their aerodynamics rather than differences in mass.
While it is true that heavier objects can overcome air resistance more easily than lighter objects, this does not mean that heavier skydivers fall faster in a vacuum. However, in the presence of air (which is the case with skydivers), more aerodynamic positioning may affect their relative speeds, and heavier skydivers may catch up slightly due to reduced deceleration from drag despite having the same gravitational pull.
To summarize, gravity accelerates all objects at the same rate, and the observed distances between skydivers are not indicative of their mass. Instead, it reflects their positions and the influence of air resistance.