If its not said players then its other players who are using said ward, no house is left unoccupied so its really a moot point that its a waste of resources.
Said resources were allocated for housing and they are being used for housing, these houses can be freed up in the future regardless.
These players who occupied an entire ward by themselves are also a unique situation which shouldn't reflect on others who may also own multiple houses be it for RP reasons or gardening.

The fact still remains however that you would rather gloat over another their misfortune while you try to justify it with resources or other poor players who aren't able to own a house due to those evil players who managed to get an extra house!