I think there are a couple of reasons. One is that we (us therapists) forgive ourselves for mistakes, and two, is that often we haven’t really done anything wrong at all and the client is angry because of misplaced transference. By the first I mean having confidence in the fact that we are 99 times out of 100 doing what is useful and if we make a mistake, we are OK with ourselves for not being perfect. The second one is about when the client is perceiving us as acting badly because they are seeing us as a family member who did act badly (transference), but we ( the therapist) actually hasn’t. Clearing that all up is called “working through negative transference” and it’s a very useful part of what can happen in therapy.
To explain further: If the client is having negative transference, they are seeing the therapist as harmful, as their parent or some important childhood figure was. They are then transferring the perception that this person is also going to harm them, onto the therapist. They are almost always transferring that onto other people in their lives also. So it’s great when it happens in therapy, and they get to realize that the therapist doesn’t mean them any harm when the therapist says “X” or looks at them “Y” – just like their mother ( or father or someone from childhood did). They may be completely right that the childhood person did intend harm and created harm, but the therapist isn’t doing that now. The therapist can explain what they meant by what they said or how they looked, or whatever.
That is so helpful to clarify. It clears up a lot of bad feelings this client may have been assigning to others in their world. It’s often hugely important.
The therapist recognizes, when the client is angry at them, if they’ve actually done something wrong and the client deserves an apology – and it’s very therapeutically useful to apologize and admit you were wrong at those times. The therapist also recognizes when the client is transferring motive, or whatever, to them and it’s not accurate, and listening respectfully and then explaining what they did intend, etc. is very powerful for the client to hear, and experience.
It takes skill and an understanding of transference to do this well with clients. It’s a perfectly OK way to use the therapist. It’s their job to help you make sense of what you experience and treat you with respect the whole way though