I see your point Curtains Up, and it is a well articulated one. However, I think the "Spam" analogy is not completely correct in this instance. This is how I personally would say a theater critic relates to a food critic...
I believe (like with food or any art or creation of any kind for that matter) a critic's role is to look at what the artist (writer, chef, etc...) are trying to accomplish and how well it serves THAT interest. How well do they articulate their vision and is it a satisfying representation of THAT.
For example, (using your food analogy) the French Laundry in Napa is trying to do something completely different from say Dreamland BBQ in Alabama. However a food critic's job is not to paint both with the same wide brush of standards. One might say Dreamland BBQ (a "guilty pleasure" of cheap, rustic regional cuisine) is just as delicious a dish as something from the French Laundry, even though it is not "high cuisine" and made for almost exclusively the masses... or those of discerning taste who wish to get their hands dirty.
I have not seen Disaster so I can't comment on that show specifically but in general I think a critic can and should judge a show like that based on it's own merits and not in comparison to say, "Hamilton" (which is arguably trying to do something very different).
Also comedy is tough to judge. It is far more subjective than drama. What is funny to one is not to another, and the one thing you can never do is explain to someone WHY something is funny. It is a losing endeavor. Thus it makes critique of comedy incredibly divisive.
I personally love a good "fart" joke and hate a bad one. There is low brow humor that is brilliant. Again, not saying anything about this particular show but I personally have massive respect for a critic who feels confident to articulate the merits of a well crafted fart joke rather than one who dismisses that sense of humor out of hand because of some pseudo-intellectual insecurity.
