In this clip from the movie Stranger Than Fiction, Ana Pascal (Maggie Gyllenhaal) tells the tax-collecting protagonist to "get bent," followed by the entire room erupting in judgment solely based upon the man's employment. In his mind, what he is doing seems unethical, yet he finds himself receiving a paycheck week after predictable week in support of the soul-stealing empire.
Similarly, in Jesus' day any Jew that was hired as a taxman was considered to have betrayed his kin by collecting taxes for the empire that occupied them. So tax-collectors were resented and despised by everyone they passed by (they were easily recognizable by their imperial garb).
Understanding this, Jesus had a habit of befriending those whom society had branded as untouchable, along with many other types of social outcasts (diseased, mentally ill [i.e. demon possessed], and crippled). In fact, Jesus told several parables detailing the surprising truth that His kingdom was precisely concerned with accepting those whom society had rejected.