The magic word is "within reason". And I count the "Xykon cannot be level 27, he must be lower to be consistent with what we saw before the Darth Vaarsuvius Indicent" to be within reason.
Yes, your opinion might differ. But taking a statement from a discussion and exaggerate it to make it ridiculous is not something I'd consider a valid argument for or against something.
Provide an argument "within reason" that Vaarsuvius is level 15 and make this option at least probably on a significant level >5% or >10% and also able to survive a casual application of Occam's Razor and we (I cannot speak for others) can start talking.
Note: Your link is/was broken. Also, I'm not sure if that is a legal source (so I did not fix it).