First of all, an old lady like that cannot throw hot water that far, he could have backed up if he was worried. He didn't like Christian rhetoric of any kind. Rebuke means to change one's mind, it is not about doing exorcism, which many Christians believe. They know before they show up now a days who gets favors, who doesn't, and who they are supposed to incite violence with. This tactic is also done in hospitals too. This is why there are so many of them and so few of us, because this has been going on for at least 2 decades.