Jesus took this opportunity to emphasize the nature of his call: He was not interested in looking good for the critics. He agreed these people were in need of reformation, but he did not intend to insult them. He said, "I am come to call the sinners to repentance." Jesus was associating with those who needed what he provided. Of course, we all need what he provides.
Did you ever think you would want to be counted with the tax collectors? I didn't, but maybe I was wrong.