I disagree.
I am in the midst of a foundation-shaking rupture with my t of 3.5 years. I am powerfully attached.
The rupture has been horrible. I have thought about quitting therapy numerous times and been self destructive. I've also learned that while my therapist made mistakes I also have powerful distorted thinking in relationships and this is making it clear.
Understanding what the relationship is and is not is essential. If by "attached" you mean " I want my therapist to be more than my therapist" that part is hard but for me I am starting to learn it's part of a broader habit of wanting people in my life to be "more" due to the extensive early abuse and neglect I experienced. Learning to accept her for who she is and what she can give me is the first step in learning to accept everyone in my life for who and what they are instead of what my child self needs them to be.

There is SO MUCH for me to learn here in the center of this pain. Of course, my T has needed to help me and has a great deal.

In all relationships the trust has to have some resilience but not too much. I find I either become overly upset about small shifts in the relationship OR I silently absorb rudeness and even abuse....but learning how to give enough of myself without losing it is a long process.

So I think the attachment is worth it. Also for me the fact that I genuinely love my T and still hoped she loved me is what made me keep coming back when it's been so hard. The relationship draws me back and supports me so I continue to work on my stuff