It's a similar situation to terminology for the atom.
It originally in Greek meant "the smallest indivisible unit of matter".
Scientists then took the name and named various elements (hydrogen, gold, etc) as various atoms.
So, this is like when computing took the idea of a neuron as "the smallest indivisible unit of memory and calculation" and ran with it.
Fast forward to now, when we know that each "atom" has a bunch of smaller stuff internally, but by now it's too late to change the terminology.
And now we also know that a biological "neuron" is something more like an embedded CPU or FPGA in its own right, each with a bunch of computing and storage capability and modes.
