I don't recall how the natural expansion deals with coal, but I'd think it'd be tagged as a strategic resource, and then it receives high priority. Just look at the nearest plains-horses in Chrin67's picture, it was already in even before Chrin67 himself could see horses.
It is indeed a little bit strange that food gets prioritized over a luxury, for a CS at least. Depending on other surrounding tiles, a lux can last a long time before it's taken in.
The fact that the whale tile in the picture is a water tile is not crucial, the same thing can happen with a furs-forest tile. It's because of low food value.
For the game I don't find it bad that some resources take longer to be taken in, and it's mostly a deliberate design choice. At map generation the CS's get their luxes when the CS's themselves have already been placed on the map. The map script writers could easily have written the code in a way that those luxes would always be dropped in the first ring, but they haven't. They probably wanted some randomization - map scripters like to work with variables anyway, to help make maps look 'natural', instead of adhering to a rigid pattern.
I'm quite okay with what's happening with resources and CS's, it gives some variety in gameplay. Sometimes if you're keen as a human player you can 'steal' a resource from a CS by dropping a town nearby and culture-grab such a resource in, before they have. Such a gameplay element doesn't need to be patched out for me.
The tooltip message can indeed be interpreted as misleading, but this game has a lot of tooltips and Civilopedia descriptions that are simply wrong, while this one is technically at least correct.
