Idempotency (as I understand it, what maths people might call an 'idempotent function') is a very core idea in distributed systems - networks are unreliable, stuff may get lost, or you might not get an acknowledgment back, so the ability to send the same thing 1 0r a million times and end up with the same state is useful.

Or have I completely missed the point of your question..?

I think autotune was saying that software often does shortcut hacks violating some of those principles as an optimization. This can be a topic for research into the tradeoffs (e.g., CAP theorem), but may be more common in non-research-based implementations (e.g., NoSQL databases because ACID is slow/constraining/etc.)