It looks like there was a woman in the lab helping him out with it?In a Japanese direct, the senran kagura devs had a "jiggle lab" where they tested things like jello to "realistically depict jiggling". Because you know, actually asking women how breasts move would take far too much time...
Yep, here it is:
At this point, I would not be surprised if these idiots found IRL breasts too unrealistic.
You can go for realism without aiming for reality. Consider, for example, the move to physically-based rendering in western animated movies over the past eight or nine years. The goal hasn't been life-like imagery, but better textures, shadows and light scattering. It's sort of like the nuance between accuracy and precision.
There is a science to fluid motion and jiggling, and you can realistically and precisely simulate that without accurately modeling the correct subject and still get results that feel better to the end user than a naive approach would.