Or, how many of the oh-so-pious would actually marry their brother's wife if she was a real piece of work because they think the Bible demands it?
There are other cases in the bible where one version of an account or a directive doesn’t fill in all the details. We’d never know, except for Deuteronomy, that it required 2 or 3 witnesses to carry out any of the death penalties mentioned in Leviticus, for an Old Testament example. And this was always the plan: it’s not like God said oops, this is going too far, let’s adjust it.
Ever since the church got mixed up in government, it regressed back into official policy of rules over grace. It wasn’t the Lord’s heart that innocent spouses sinned against should be under mandatory bondage. Pushing this too far only resulted in the church splitting, because rules over grace must needs be about men. Till we got the modern version of Roman Catholicism which is something like 10 parts intrigue to 1 part Christianity. We don’t even see that degree of intrigue from the Orthodox (which also is why they never really had their widely popular version of Protestant, to be so disgusted they could see no choice but to go worship God separately).
I believe the Lord will work it some day to reunite Christendom, and it will look like something that nobody quite envisioned when it does. But it’s not going to be under the rule of men that it reunites.