When I enable the "Show on Zone Map" option under Dungeons / Raids, only the dungeon portals are shown on my raid map. The similar "Show on Continent Map" shows both dungeon and raid portals on my continent map.

For example, in the zone I am currently levelling, Dragonblight in Northrend, the Wyrmrest Temple and Naxxramas raids are shown alongside the Azjol Nerub dungeons on the continent map, but when zooming in to the zone map, only Azjol Nerub is shown.

Note that I do also have ElvUI enabled and have not tested without it, but I can do so if this behaviour is unexpected.

They do on my zone map.