Various definitions of "
Hack"
To use one's skill in computer programming to gain illegal or unauthorized access to a file or network
To alter (a computer program)
To write or refine computer programs skillfully.
As you claim Nodus is a recoded version of Minecraft:
Nodus was essentially Minecraft recoded
Wouldn't that pretty much be a "Hacked" client?
These are all "Hacked" clients, even clients with only OptiFine installed, as they are "Altered" or "Refined"
However, you do prove a few valid points, and I thank you for pointing them out.
But you must remember that this is the MCG (MCGamer or MCSG) Community, and is allowed to make it's own rules, regulations, and terms: In this case, "Hack" refers to things such as Xray, Nodus, etc.