“On the other hand, there were no significant differences in how white conservatives, including Republican presidential candidates, spoke to white versus minority audiences”
The referenced study does not indicate what type and sizes of black audiences were being addressed.
It seems to me that black audiences would be very different in size and age group, etc. that listen to conservative or liberal speakers.
I don’t see what control the researchers used to make the determination that white conservatives speak the same to white and black audiences while white liberals speak down to black audiences and up to white audiences.