Ok, I understand your view on the matter and how you and your team arrived at the expectation you laid out.
Now, I won't try to defend the way the Star Join view is provided, but I like to point out, that there are more than one types of requirements for such value help views.
One approach for those is to say: show the user every possible value (based on the available data in the dimension/master data).
Another approach is: only show the values for which there are actual records in the fact table (booked values in an InfoCube to use BW terms).
Both ways can be reasonable and by simply querying the dimension column in the star join view, you are following the second approach. And this makes sense also on a semantic level: you query dimension data in the context of this specific cube.
One important point about the way dimensions are modeled is that these are also calculation views of type dimension. This enables these dimensions, actually representations of master data, to be shared and reused in multiple cubes/star join views.
It also allows to access the master data outside the context of a specific cube. And this is what you seem to want to do here.
In order to model this in SAP HANA you can choose a table or calculation view and assign the to-be-filtered column in the star join view/cube separately:
Note how I selected my dimension view devTest::dim10 here as the value help input.
It could've also been a base table or a completely different view (maybe one that would show more additional information).
This way of modelling allows for you to have it "your way" of displaying the value help data easily.