I can’t speak for Belvedere or Huber. But it’s possible to argue that consequences are unimportant to the moral considerations. For example, under Kant’s Categorical Imperative, one is only responsible for one’s own actions. Applied to your example, it would mean that women who choose unsafe abortions are responsible for that choice, not the people who outlawed abortion, even though the latter eliminated (or at least sharply reduced) the option of safe abortions.

In Part 7, Belvedere makes a similar point distinguishing a deontological framework from a utilitarian framework.

I have strong objections to the Categorical Imperative, or any moral framework that ignores real world consequences. In the case of outlawing abortion, if the result is a similar total number of abortions with an increase in the number that are unsafe, then I’d say outlawing abortion failed and the society is now less just.

It’s possible to counter my position by claiming that being “morally correct” is essential, even if the results are negative. I think that’s a self-righteous prioritization of personal purity, and no way to run a country. At a philosophical level, I’d argue that this line of reasoning mistakenly equates individual moral standards with a just society.