> it possible you haven't understood the rules
Yes, that's possible. But the (ostensible) rules of originalism are not exactly rocket science.
> Following the 14th Amendment, there were no anti-miscegenation laws (or they lingered dormant).
That statement has the form of "Santa Claus exists (or the sky is blue)." It's technically not false, but it is not a good-faith argument either. There absolutely were anti-miscegenation laws in 1865; such laws date back to 1691. So there is absolutely no possible originalist justification for Loving. When Loving was decided, anti-miscegenation laws had been on the books continuously since long before the United States even declared independence from Britain.
>That the 14th Amendment was democratically -- if contentiously -- adopted by the people with the express consequence of ending racial discrimination (education, marriage) is a ridiculously easy case to make.
None of that is even remotely close to being true. You are either not arguing in goof faith, or you are profoundly ignorant of history. The passage of the 14th Amendment was followed by 100 years of uncontested Jim Crow laws [2]. Even today the Republican party is hard at work finding new and creative ways to disenfranchise minority voters [3-8, and I could have gone on and on and on].
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[1] https://en.wikipedia.org/wiki/Interracial_marriage_in_the_Un...
[2] https://en.wikipedia.org/wiki/Jim_Crow_laws
[3] https://news.berkeley.edu/2020/09/29/stacking-the-deck-how-t...
[4] https://www.nytimes.com/2020/11/22/us/politics/trump-republi...
[5] https://www.npr.org/2018/10/23/659784277/republican-voter-su...
[6] https://pbswisconsin.org/news-item/republican-election-tacti...
[7] https://www.brennancenter.org/our-work/research-reports/new-...
[8] https://www.washingtonpost.com/politics/interactive/2021/vot...