Any number of people spend their lives being told to be nice, don't express unpleasant feelings, take it and shut up, don't complain, etc. I think it is good when someone speaks up to a therapist and tells that therapist how they feel about what the therapist did. And it does not have to be nice, correct, pleasant, etc.
So when they speak up about it - it is to be applauded - not criticized for not being nice, or thinking of the therapist and letting it go because the therapist is such a good guy usually or etc. In fact, I believe, therapists themselves set it up so that there is not normal human give and take at appointments. A client gets to tell a therapist when something they do upsets the client regardless of whether that is the nice, polite, be a good girl response or not.