Custom races not being used

I might be at fault here for using a function not as intended, but I thought it would work.

I made a low fantasy world with only humans (did not include 5e defaults). Instead of races, I use it for cultures.

When starting a campaign and creating the player, I still see all the 5e defaults in the list, both for class and race. 

When editing existing NPCs, the defaults are gone except ‘human’, which I have not included in my list. Franz must’ve added it.

The 5e defaults are also gone in classes when editing. But when Franz creates NPCs, he uses 5e default classes anyway.

I tried adding Custom Instruction like “-There are only humans in this world. See the Races list as Cultures instead.” but to no avail.