There is nothing wrong with light beer! There, I said it. Now you should know that I consider myself a beer snob, I’ve knocked it plenty myself, and I don’t defend it blindly. I wouldn’t even say I prefer it, but I think it deserves a healthy measure of respect. Enter snobbery in favor of light beer.
Beer isn’t an either or thing, it’s not exclusive but broad and inclusive. Beer comes in a veritable matrix of continuums (continuui?) from light to dark, bitter to…less bitter, high alc % to low. Malty, yeasty, grainy, fruity, sour…the list goes on. Light, crisp, drinkable are just as valid as heavy, roasty, hoppy or full bodied. A sensitive palate and perceptive, intentional, conscientious consumption can tell you a lot about what you’re drinking, but it can’t tell you that one style or flavor is preferable to another. Only your personal inalienable preference can tell you that. Snobbery ought not preclude the right to your own tastes.
The most sensical sommeliers (my opinion) will tell you that you’re not wrong for what you like and prefer, even if your knowledge is low; of course the potential for a grand experience rockets upwards as your knowledge of what you’re tasting increases.
Light beer is not lacking. It’s not a thing characterized by lacking quality or tilth (though this would accurately describe many mainstream examples) as many might suggest. Rather its aspects are lauded as a matter of preference, substance and character.
That said, mainstream light beer is not a thing of beauty and it far lacks the flavor of its carefully brewed companions. As with many things produced corporately, corners are cut and a good thing becomes but a shadow of what a quality example might offer. Major brands are indeed lacking careful production, but it’s not a fault of the style, just of the masses indistinguishing palates. “Piss-water” isn’t a fault of the style, but of laziness and stinginess.
If dark beer were truly objectively better, then why do we have light beer at all? From the historical perspective, all beers were once dark, they’re easier to make. Lagering in fact takes additional weeks or months of aging and temperature control to arrive at this light and golden drink (yes there are dark lagers too).
So basically light beer should be lauded (if you like it) but never scorned. If you want to get specific, go ahead and scorn the poorly made varieties, but don’t knock the style.