As far as I can tell, EGP (Exterior Gateway Protocol) originally
used the term "neighbor." Berkeley used the berkelism "peer" in
their software and RFC 911 documenting their experience, and the
term stuck through EGP2, BGP1-4.
If we still used the word "neighbor" would the phrase "Are you
a neighbor?" have a different ring than "Are you a peer?" You
can have lots of neighbors, even if you think you are superior
to all of them.
You're thinking about this too much. The backhoes must be behaving today!
;-)