I tell my own clients to avoid agencies if they can. Often the people that work there are or have narrow minded rules and regulations and the workers are unwilling or unable to go outside their box.
There are very few Federal rules or laws that apply uniformly to therapists across the united states. Certainly no therapist must keep working with a client when the therapist themself is too insecure or controlling or whatever to be able to deal with it when the client does not just roll over and let the therapist boss them around.
Each state sets their own laws and regulations about the industry and how to license etc. The three states in which I am licensed to practice law do not have any rule about meeting with a client twice and then getting a restraining order against the client if the client does not agree to roll over and submit to the therapist. It is also not that easy, in my jurisdictions, to get a restraining order just because you are mean to someone - even a therapist. A person has to go pretty far and be credibly threatening and harassing = not just criticizing, even in a mean way, during an appointment - even if the person did so more than 2 times.