Maybe you missed it but that is not what Lyristeon is stating at all, there is nothing to do with aging going on at all in the current rationalization put forth.

You could for example cause milk to "age" faster by leaving it on the table instead of keeping it chilled. This accelerates the aging process, wither does not do this. If milk aged as if it were afflicted by the wither commune it would be perfectly fine up to a given point then suddenly spoil unexpectedly but in reality it slowly spoils on the table getting progressively worse just at an accelerated rate from what it would experience if kept in a chilled environment. This is aging as defined in your definition, to cause to become old but this is not what is happening in regards to wither.

The problem is the current implementation of wither and helpfile do not accurately reflect what is occuring. I would prefer to see that the age state of the afflicted is changed it makes more sense and would not lead to surprise early deaths.