Anyways, the correct link is https://pluralistic.net/2021/10/20/vizio-vs-the-world/#capit....
In THEORY, when the fragment is (semantically?) significant, the site could dynamically alter the link rel="canonical" value to include the fragment such that you could check whether to keep it or not, but in practice I think that canonical links are intended for web crawler deduplication and so nearly always strip fragments off.
About the only thing I could suggest would be to add a checkbox to the submission form that controlled fragment-preserving vs stripping, but you would probably need to add a review queue to double check it wasn't being abused (not that abuse is a particularly attractive target, in this case), and I am unsure whether the minor additional code and UI complexity is worth it vs. the ad-hoc process you have now.
A second possible approach would be to invert that suggestion and simply add a review queue to check whether a removed fragment should have been preserved instead (ordering or filtering the queue by the rank of the submission rather than chronological order, for sanity purposes).