Probably b/c you don't understand REST and its history?
Kizer says>"I can't summon any kind of compelling justification for a restriction to only GET, PUT, POST, DELETE - aside from their analogy with CRUD I guess."
That is an invalid analogy, but your desire to know why it is an invalid analogy may motivate you. Learning about REST will enlighten you.
Kizer says>"Could anyone please enlighten me?"
Unfortunately enlightenment is something one must gain oneself. Google for "Representational State Transfer REST" and follow the most interesting URLs until the light bulb goes on. Or try:
https://www.google.com/search?q=best+introduction+to+represe...