Except that the trend Morrison himself was criticizing wasn't applicable to either the comics or the movies at the time and had pretty much died away. As I said, this take on Diana is largely only an issue in elseworlds or writers who have a bone to pick with her not matching up to some weird pacifist take on the character that never existed. Remember that Morrison was complaining about Diana in BvS just for having a sword before the film ever came out.
From JLA we have how Johns wrote her and in his original JL run Morrison didn't exactly expand much on her other than the warrior thing.Do you have any examples from JLA or Earth One? I can't recall any from either of those. Even in the bad future of Rock of Ages, I don't think she does anything too outrageous or even uses a sword.
It's been consistent with how DC heroes treat the killing of non-humans. Morrison himself had Superman say his rule doesn't apply to sentient machines.They are flaming hypocrites because Rucka wrote them to be that way to make a point. Another writer could have written Superman as having an issue with both deaths. There was precedent for both of them.
Like you said, Rucka didn't write this in a vacuum.