The point is that defenders of the DCEU don't all think other versions of Superman are flawless (though I'd say that the Silver Age's version wasn't so much that he was flawed but that the writers didn't really seem to know he was flawed). And again, Johnson himself stated that he prefers Superman as a guy who makes few if any mistakes and is someone "we aspire to be" (see for instance his comment about Superman and Lois).
Whether or not Snyder executed his ideas well is up for debate but it can't be denied that a large or at least very vocal segment of the Superman fandom felt it should not have been done at all.