To confirm: Both answers were deleted by a mod, but in both cases at least one other user voted for deletion. With or without a mod's unilateral vote, they were going to be deleted at some point.
I'm not going to speak for the mods - I have a feeling at least one will answer - but a custom flag could be used. If the community decides that these answers should be deleted, I think that would be the best option.
But there's a good chance that we should just downvote these things. For example, take this post on Physics. The decision was that non-mainstream - in this case essentially pseudoscience - answers are acceptable because they address the question. Like it or not, they're valid.
The reason you can't carry over the reasoning from questions ("we have a non-mainstream close reason, why not delete non-mainstream answers?") is that, first of all, answers are not questions. They fill different roles in the site and there's no reason to expect the same sets of rules to apply to both. Beyond that, our non-mainstream close reason is mostly meant to curtail a specific kind of request: that where someone posts their pet theory that is going to overthrow relativity (or whatever) and challenges us to find something wrong with it. Requests like this are a drain on the attention of professional physicists and grad students (check your spam folder :-p), and we don't want to entertain them on this site. Clearly, this is only an issue for questions, not answers.
I think he has a point, though I'm on the fence about whether or not it's always applicable. In these cases, nobody has a "pet theory" that they want someone to discuss; they're just posting a poor answer.
I also started a mini-discussion in Physics chat (The h Bar) the other day about it. ACuriousMind said something regarding a post I had brought up regarding dark matter:
It's a bit weird because the non-mainstream nonsense there says there is no dark matter, so it would answer the question, if it were right, by showing that the premise of the question "there is dark matter" is flawed.
I have to agree with that logic. These posters are wrong, but we kind of have to let them post them so long as they attempt to address the question. And it can actually help, too, because we can use those posts to comments on misconceptions people might have. If the asker happens to be thinking along the same lines as this poster, we can correct him/her and better explain the concept.
So I leave it. But if the community decides to delete these answers, then a custom flag seems like the best idea at the moment. I'd like to see what the mods say, though.
By the way, Earth Science had a related meta question recently about pseudoscience questions.