I don't know of any map that renders amenity=hitching_post or amenity=animal_hitch. This will certainly not happen with the maps offered on osm.org until thousands of such things have been mapped. So far there are only a few hundred. Even leisure=horse_riding, of which 19k have been mapped, is only rendered on a few maps so far, see https://wiki.openstreetmap.org/wiki/Talk:Tag:leisure=horse_riding#Rendering. To see the horse highlines on a map, you could add another tag, which will be rendered. But to do that would be against OSM conventions, see https://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer. Or make your own map using the OSM data.

These tags are also not in the presets of the editors. For iD you can open a request like https://github.com/openstreetmap/id-tagging-schema/issues/233. For JOSM you can add a preset in https://josm.openstreetmap.de/wiki/Presets/NewTags yourself.

If you don't object, I will retag the horse highlines. Do you think that horse highlines can be called hitching posts? If not I will will retag them to amenity=animal_pitch + animal_pitch=xxx; should xxx be "highline" or "high_line"? There are also "picket lines" (two words), see https://en.wikipedia.org/wiki/Picket_line. Can you upload a photo without copyright restrictions of such a horse highline on wikimedia commons or in the OSM wiki for the documentation in the wiki? https://commons.wikimedia.org/wiki/File:Highline.jpg is not suitable because it shows a temporary highline which therefore should not be mapped in OSM.


