But the fact is, as evidenced just from what we see right here on this forum, there are many times when the T really has done absolutely nothing wrong yet the client, because of their own history and triggers, absolutely reacted in a way completely disproportionate because they perceived a hurt or slight when there really was none.

That said, a therapist (well anyone) should apologize when they have made an error that causes someone pain, and they should work to correct that error.

But I completely get the "I'm sorry you feel that way" response having lived with a husband who, because of his history, often reacts completely through mis/over-interpretation. I don't apologize for "causing" his misinterpretation/reaction anymore. That was crazy-making. I do say "I am sorry you are feeling so badly right now. I hope you'll feel better soon" or something of the like when I know his reaction is his to own and truly has nothing to do with anything I have done wrong. I've learned my "owning" my husband's issues does him no favors at all and ends up enabling some really poor behaviors on his part. He does better when I listen and we talk things through so he gets his head wrapped around what set him off (which usually isn't me at all; he's just reacting as if it is me because I'm in front of him unlike the ghosts of his past.)

I suspect therapists have to walk a similar line between being understanding of where a client's reactions are coming from and knowing when their own actions are actually causing the problem.