From Glossary in Rules
RNG - Random Number Generator, which is a legit method to breed/catch stellar IV or shiny Pokémon; a guide is *smogon.com link removed*
Nah, RNG is considered legit because it requires the use of an external computer program, not an external device.
One does not need an AR to perform RNG abuse. ALSO, one technically does not need the program to calculate the seed/frame/delay/blah, if one is a relative of Einstein like moi.
If ya gonna ban the external program of the RNG Reporter, ye might as well ban the common internet resources and programs such as idk Bulbapedia, Metalkid, Serebii, Shoddy, etc. They help tell you where something is. A TM is at Route blah. A shiny is at frame 312. Woz. Me thinks.
Unfair, perhaps, but pre-RNG, anything with flawless IVs was generally considered impossible/hacked. At least RNG is refreshing for those perfectionists... Plus, I have done my years worth of IV breeding. Do not complain about a few weeks, mm? I still find RNGing difficult; I probably finish in a few hours, not 10 minutes, shame on me.