A therapist is like a stockbroker? I don’t understand how.

A stockbroker has expertise in investments and a license to sell them. They give expert advice, albeit motivated by their own personal gain, and they sell you an investment getting paid by commission. They do have a fiduciary responsibility not to do something unconscionable to the client.

How does a therapist compare to this???

I do understand what you are saying though about getting scammed by the therapist’s motivation for their own gain.