To make a straw man of Taruskin's own argument, what he's saying can be summarized as follows. There are two basic types of performers: those who don't care at all what their audiences think, because they see themselves merely as media through which the composer is communicating, and those who are trying to make music for an audience to enjoy. (You'll have to trust me that my oversimplification is nothing compared to his own caricature of the music world.) In reality, the situation is much more complicated, and he only captures a small portion of it in his article.
In the real world, there is music like Tchaikovsky's, which, in my humble opinion, though often pleasing enough, generally doesn't compare (with a few exceptions) to the music of his superior contemporaries, tuneful as it may be. There's the music of Mahler, which, though it's often impossible to appreciate on first listening, or to a novel ear, reveals its greatness with a little work on the part of the listener. But there's also pop music, which, obviously, listeners enjoy a lot, but we don't perform at Carnegie Hall.
The point Taruskin tries to make is that, since audiences like Tchaikovsky and Horowitz, we must be snobs if we criticize it. But does that make us snobs for not appreciating Tik Tok and Taylor Swift the same way we revere the Goldberg Variations? Taruskin's problem is that, while he rightly acknowledges that performances of classical music often miss the whole point of appealing to an audience and sharing great art with them, they can also be overly indulgent of an audience's baser desires and tastes. People love it when a pianist goes on stage and wows them with the sheer physical achievement of something like "flight of the bumblebee," but the whole point of "art" music, whatever the point is, is to get beyond an obsession with the performer and get an audience to appreciate music for its own sake. This distinction is, after all, what separates the world of "classical" music from the world of popular music. (That's not to say that pop music can't be good, or even great, but just that it isn't generally composed to be listened to with full attention on the music.)
Where then, do we draw the line, then? Surely what we want is a middle-ground, where performance is about music, not about a mythical composer, or about a mythical performer.