The fact of the human condition that Hawthorne alludes when he mentions the need for a prison and a cementary is that human beings aren't perfect, all people sin, and thus, there will be crime and death (original sins) too.
Step-by-step explanation
Showing the need for a cemetery and prison, allows Hawthorne to demonstrate that humans are imperfect and sin, as well as it shows a comparison between spiritual and physical imprisonment, which is a metaphor that appears in the book. Moreover, the prison is a symbol of disgraced people.