What is missing here?

Seems like the essential issue the OP is questioning is the responsibility of the reviewer. He's insisting the reviewer should educate the 'casual listener' on not just this amp, but how amplifier output and distortion generally relate to speaker sensitivity. Can't say I agree with the premise, and I'd assume the reviewer would not either.

And, I'm not sure "How many even somewhat seasoned a’philes have made the mistake of matching a flea powered amp with a less than favorable speaker load?" Seems like making a true mistake would be indication of pretty light seasoning, as this probably implies ignorance of Hifi basics, standard research prior to purchase, in home trial with knowledge of return policy, etc.

I am just wondering, what folks think of Art Dudley's ( RIP ) review of this amp in the January 2019 Stereophile Magazine. Although reviews are always " good " these days, for reasons discussed above, I miss the writing of A.D. Enjoy.....

@daj That is precisely what I am getting at. Although you seem to negate this, I believe that a reviewer has a responsibility to a reader to educate them as to what the possible issues (failings) of the product are...and not, as some of the other members here have commented on...simply to write advertising prose. Like Atmasphere commented above, this omission is actually pretty important, and leads to a failure on the reviewer’s behalf, IMO.

The amplifier has no "failings". It is exactly what it purports to be and will work well as intended. There were no "omissions". The power output was listed in the specifications. Have we gotten so mentally lazy that we need to be told that we can't play an LP in a CD player?

The amplifier may not have failings in doing what it was designed to do, within its very very limited parameters. That’s not the point here, what is the point is that the reviewer never brought up the limitations that are inherent with a design like this. I think these limitations are severe enough to disqualify this amp from most people’s ability to utilize them successfully. Since there seems to be some disbelief that folks would buy this amp without already knowing its short comings, let me relate a story that happened recently to a very sophisticated and experienced audiophile friend of mine...This gentleman goes shopping for a new amp for his fairly inefficient speakers from the same dealer that he had acquired the speakers from. The dealer sells him a low powered amp that ‘should’ work with his speakers and in his room. My friend believes that this tube amp should work, as it had a very favorable review in an audiophile magazine with good crede. Unfortunately, after about a month of trying to get the amp to work well in his system, he came to the realization that the amp in question was simply unable to properly drive his speakers, resulting in not only a ton of frustration, but ultimately a significant loss when he came to sell the amp!
Now, IMHO if the dealer or the reviewer had mentioned the fact that this amp has severe limitation in its ability to drive less than ultra efficient speakers, do we all think that my friend would have made this mistake?
BTW, I’m not saying an Air Tight dealer would lead a buyer on in this regard with reference to this particular amp, but again, the reviewer said nothing about the amps severe limitations ( ok,different from failings). An omission that I believe was significant and unfortunate.