I find mods retitling links to be a strongly positive feature of HN. It is one of those things thats very touchy though, but it'd be a shame if people's territoriality meant we had to accept wrong and misleading titles.
For what its worth, whatever was wrong with the original title I feel like yours was pretty misleading after going and reading the article (great article by the way, thanks for sharing it). The article was very explicitly about the library congress meeting to talk about the origins of the map, rather than a general piece about the map. If thats all you found interesting, perhaps you should have linked to a wikipedia page or a more general article.
For what its worth, whatever was wrong with the original title I feel like yours was pretty misleading after going and reading the article (great article by the way, thanks for sharing it). The article was very explicitly about the library congress meeting to talk about the origins of the map, rather than a general piece about the map. If thats all you found interesting, perhaps you should have linked to a wikipedia page or a more general article.