Books like Huck Finn are critical to building the model in your head that every writer has a different perspective, that they will present differently, and even perceive differently. (Is Huck exaggerating to you the reader? This is a critical intuition to get about all writing to make you more literate, not less.) You learn to understand through different writing styles, which is another absolutely critical step in becoming literate.
Just thinking about a world where we take your advice above makes my stomach turn it seems so wrong to what the point of reading these books even is…