It is important to realize that third person + don't is bad English today, but that was not always the case.'
In the 19th century, many educated people in England and the United States had no problem in saying third person + don't. For example, President Woodrow Wilson (1913 -1921) reportedly used third person + don't in private conversation. But when he spoke in public, he always remembered to use third person + doesn't.
It seems that teachers in the 19th century kept insisting that only third person + doesn't was correct. So little by little that became the correct form.
In my opinion, if a politician used third-person + don't, she or he would never be elected president, for people would lose respect for him or her.