Each eye has around one and a half to twice as many neurons (high estimates put the number between 120 and 150k, low estimates at 75-110k), roughly, as the heart. Ergo, I exist in my Stomach, Two Eyes, and my Brain more than anywhere else in the body? Also, depending on some estimates, the lumbosacral plexus has more neurons than the heart (150,000 for motor control of each leg, give or take depending on well-known estimates)… So my thighs aren’t just thick, they’re also a seat of neurological control.
We also have like 8 Ganglion clusters (sub brains, if you will) that allow for autonomic control of organs when BigBrain 
isn’t functioning correctly.
Also, at best there is a strong (but increasingly weak in larger studies) correlation between Neuron count and neurofunctional complexity. It helps to read more literature than the one paper that is found to support a chosen argument…
https://d-nb.info/1332809901/34
https://karger.com/bbe/article/99/2/109/860281/The-Relationship-between-Cognition-and-Brain-Size
To the point of this: It is not “neuro-reductionist” to focus on the brain as the seat of Neurology in the human body. Take away the brain entirely and we know that these substructures stop computing. No one involved in the study of neurology thinks we are entirely in our own brains, but they do think the brain is the core element of human neurology.