The Short Version
The claim captures a real feature of quantum field theory but significantly oversimplifies it. The Feynman-Stueckelberg interpretation does treat antiparticles as mathematically equivalent to particles propagating backward in time, but the rigorous symmetry — the CPT theorem — requires simultaneous reversal of charge, parity, and time, not time alone. Reducing this three-part transformation to "reversed time dynamics" omits essential components and gives a materially incomplete picture of the underlying physics.