...this glosses over the concept of the individual.

This misses the mark, I think. Here's a mutation:

"It is in interest of each and every cell to unify (coordinate) more with other cells, so this glosses over the concept of the organism."

The coordination of cells is what allows us to speak of an organism as a whole. I won't go so far as to declare that co-ordination of agents justifies the concept of the individual, but I do think the idea expressed in the parent is more wrong than right.