Puritanical bias refers to the tendency to attribute cause of an undesirable outcome or wrongdoing by an individual to a moral deficiency or lack of self control rather than taking into account the impact of broader societal determinants.
[1][2] An example might be, "These people sit around all day in their apartments on welfare watching TV, but won't take the time to get out and find a job!"
Where puritanical bias differentiates itself from the two is in specifically concerning only unpleasant and unwanted behaviours, by explaining them only through negative dispositional characteristics.
This would be an example of fundamental attribution error, as situational factors have been under-emphasised in comparison to dispositional qualities in explaining a seemingly altruistic act.
[18][19] In disproportionately attributing individual-level explanations to undesirable outcomes, policy-makers absolve themselves of blame by displacing social issues onto those who suffer most from them.