Not rigid. Not arbitrary.Nope. Rigid and arbitrary. If you understand how TAC counters work, and the tactic in question, you'd see that this is no different than punishing a normal's recovery with Guard Cancel X-Factor. TACs rules are left intact and unaffected. X-Factor is simply giving us another option to take liberties with the game's systems - just as it was intended.
X-Factor does a few things:
Provides a damage boost (varies by character)
Provides a speed boost (varies by character)
Puts character into a neutral state, cancelling any actions the character was taking.
Resets Damage Scaling
Resets Hitstun Scaling
X-Factoring cancelling the first TAC to try a second TAC is fine. The opponent not being able to counter ANY of the 3 TAC options for the second TAC? Not fine. It's allowing a bypass of a game mechanic. Glitch, and as we're not in the dark ages anymore, it'll get patched eventually. There were people who thought the DHC glitch would survive. They were nuts.