Few can say what they mean on the first try. When men use words carelessly because they don’t know how to use them carefully, they may mean something deeper than what they say. Look at it this way: Words often have a thrust more than a point.
As this applies to normal people, several points crop up. Most of this is old hat, easily filed under “Listen, don’t just hear.” Ask for clarification. Try to understand. Without this, you may “win the argument, lose the person.” This also applies to the hostile.
To illustrate: If someone asks about the Inquisition and will not hear an answer, moving on to the Crusades or the recent sex-abuse scandal, he does not seem to want an answer to the question his words form. Therefore, do not start by giving him an answer, at least to the question on the surface. Answer the question he meant, by anticipating it with a good version: “Why should I believe in your Church if she sins?” This is is a good question. When anti-Catholics bring up the sins of the Church, find out if they want an answer to that question. If so, or if there is some other good question like it, take the conversation from there before descending into particulars.
However, if he still will not hear this answer, instead jumping around from stick to stick — — call him out on it. If he does not really ask a good question but poses as if he does, playing along will only hurt him. We would only confirm him in his self-delusion. That said, don’t be quick to dust off your feet as a testimony against such a person. It takes care to know the difference between authentic and posturing anger, and, as evangelists, a failure to discern what they mean is not their failure. It’s ours.