I think it is is a fallacy to rest upon the idea a therapist is trained. First, they (at least in this country) are not all trained to cope with their issues. Here, you can be a licensed therapist without ever having been in therapy yourself. Second, it depends upon their theoretical orientation. Third, among those who are trained, some are just simply better at it in general than others and they do react to different clients with varying degrees of ability to handle themselves and the client.