The dopant atoms are part of the same system, and they are contributing electrons which are fermions. Thus it is obvious that these electrons should follow the Pauli's exclusion principle. However it turns out that all the electrons provided by the dopant atoms are present at a discrete energy level. According to me(Just a speculation), there should have been a separate band corresponding to the dopant atoms formed somewhere between the band gap of the crystal.
The dopants form localised states just above the valence band or just below the conduction band depending on the dopant type. These are separate localised states with at most very limited interaction with each other. They are too widely separated to form anything resembling a band. There is no problem with the exclusion principle because the electrons from the dopants are not trying to populate the same state.