A ton of "incorrect" comma usage isn't even (historically) wrong, actually, it's just currently unfashionable.

There was a reaction in the last century against poor writers with poor taste over-using punctuation and writing ugly, long sentences. The result was stern advice to students to eliminate punctuation and cut sentences up into tiny bits. These same students came out of this process believing this was correct writing, not a straight-jacket put on them to keep them from hurting themselves. They unthinkingly cite Hemingway and borrow his clout, I suppose judging almost all writing before Hemingway and most after him, up until the 80s or 90s, as "bad" even when it's the work of masters. They blame the author when their stunted literacy (learning to write can hardly be separated from learning to read, at least at the more-advanced end of "to read") leaves them, as adults, struggling with texts once meant for children.