>>213636590
It's not about acting, it's about anatomy, and the foot and leg angles created by the PGF subject while it's walking defy what human anatomy is capable of when we walk. About the closest we can achieve to those angles is our running gait.

>>212467520
The sasquatch and gibbon both create foot angles almost perpendicular to the walking surface, create lower leg angles that are almost horizontal to the walking surface, and neither locks out their legs during the walking gait.

Humans don't create foot angles that are perpendicular to the walking surface, nor are our lower leg angles almost horizontal, and we lock our legs out when we walk. The only time we come close to creating the angles we see on the sasquatch and the gibbon is when we run.