If you reveal that you have classified data and even write conclusions based on the said data, people will come out and ask why. You don't get to use appeal to authority arguments on the internet and walk out without people asking for evidence for your judgment. I wouldn't ban anybody for this.
You absolutely do get to use appeal to authority if you are an authority with access to exclusive knowledge.
Ultimately not all opinions are made equal.
Yes, if someone claims to be an authority and one wants to demand evidence because of one's own skepticism, then that is that person's right to ask for it and demand for it, in context of a thorough, equal and fair debate.
But that does not make it good etiquette, polite or reasonable to do so, and this forum is not a place of equal and fair debate where all information can be openly shared.
Sometimes just because you logically have the right to request something, does not mean it is reasonable to do so.
Ultimately, I think some people can benefit to learn to choose your battles and perhaps recognizing not every inch of "CHYNA STRONG" needs to be defended and contested to the hilt.
Yet you can bet that some of the people arguing so strongly in demand for evidence would have not made a sound if the statements made were that their impression was that J-20 was superior or equal to F-22 in all domains.
And yes, I also echo tphuang's sentiments that perhaps sometimes people may be better well served to just observe, which is putting it quite kindly.