I agree. There is no reason why a "traditional Superman" could not be the core of a film, and a successful one. But my objection to the negativity thrown at Snyder's version has never been "you (general you) are wrong not to like his version" or "you're wrong for preferring a "traditional Superman". It has been, and remains, a firm rejection of the idea that a non-"traditional Superman" is, in and of itself, an illegitimate film project. There is no "should". There is "X's vision" and let the chips fall where they may.
In 1978, the makers of Superman: The Movie made the choice to present filmgoers with a traditional version of Superman as a tonic to the post-Watergate malaise of the era (an American centric motive, to be sure, but it was an American project). Totally valid choice. A wonderful choice. One I enjoyed immensely at the time and still enjoy today. But if they had chosen a less traditional approach, it would have been equally legitimate. Equally successful? No way to tell. But if Richard Donner had wanted to explore different themes than the ones he did explore, more power to him.
When Snyder (and his team) laid out their version of Superman, they asked questions that were perfectly valid to ask. How would the world react to a superpowered alien in the present? How might he have turned out if he was raised by decent people, though not the paragons of virtue of tradition? How would he cope with an extinction-level threat on what was essentially his first day on the job as an out in the open costumed hero? Whether one appreciates the answers Snyder offered to these questions does not make the questions and themes illegitimate and unworthy of exploration. Moreover, a non-traditional version of Superman (measured against all the "traditional Superman" expectations expressed by many) is an unavoidable result. One does not have to like the result. But I cannot abide the idea that the only way to do a Superman film is in the mould of "The Way Things Oughtta Be". Just as I can enjoy Adam West and Christian Bale as two radically different Batman portrayals, I can make room for Christopher Reeve and Henry Cavill (I'll leave the debate about how radically different (or not) Reeve and Cavill are for another time). At the very least, even if one does not enjoy both versions, there is room to allow for an attempt that differs from tradition.