First of all, the DCEU tag was added to the question since that is what the question is asking about by the mere fact it was asked on this site and this isn't Comics.SE but Movies & TV. You simply can't ask a question about every or any possible Wonder Woman incarnation and not have it be related to a film. But even then, we could say answers from the comics source material might be relevant additional information, provided they don't downright contradict the film content and try to at least make a cursory connection to the film.
However, your answer did neither. Not only did it not relate to the film at all, it didn't even relate to the comics source material either. You yourself say it's not canonical and just a joke. It was a supposedly funny joke comment, nothing else. And frankly, the votes on it don't really mean squat, it's a joke "answer" on an HNQ question, of course people will upvote it, that doesn't really say much about its merits as an actual answer. (Other non-moderator users on the other hand voted to delete it and flagged it as "not an answer".)
To address your specific points:
- Yes, users can improve other people's questions with helpful edits on these sites, and in order to even be on-topic the question was either about the DCEU or about the 70s TV-show. And at the time of asking the former was a sufficiently safe bet.
- He did implicitly, by asking it on this site and thereby looking for a serious answer.
- Yes, a shared universe might include a lot, and information from the source material can be relevant, too. It does, however, not include parody comics made by random internet people, unless proven otherwise.
And even if we forget all these points and concentrate on the answer itself, it doesn't even provide any information, it throws a funny picture at us without even elaborating what the conclusion therefrom is even if we were willing to accept the comic as a serious source.
So on the bottom line, this answer had absolutely no right to exist as an answer, and to say "but a lot of people found it funny" won't really change much about that.