I'll bet you don't know that there is an etiquette in therapy. Since therapists are in the business of assisting you in resolving your difficulties, they have a certain [B]SET in counseling. "Set" means 'game plan.' Think back over the previous therapists you have had. Usually they give you maybe two sessions to emote, cry, spill your guts, and vent. After that they want to identify the problems to be solved; get at the difficulties you wish to work on. They are problem solvers, and if you don't come up with a PROBLEM they can get frustrated. It may be that you only wanted to "vent" in counseling. That is a goal in itself, and perfectly fine. HOWEVER, IF THAT IS YOUR GOAL, MOST THERAPISTS WILL ALLOW ONLY A FEW SESSIONS FOR THAT.
You see, clients and their insurance companies put pressure on therapists to develop goals for treatment: a treatment plan. You cannot bill insurance without one. And depending on how detailed the treatment plan is, insurance will grant up to 10 sessions for which they will pay. Most privately paying clients do not want to languish in therapy for years, and want to deal with whatever problems as efficiently as possible (i.e., as cost effective as possible). A treatment plan which only specifies, "venting" will get only a few counseling sessions granted by most insurance companies.
Insurance companies are not your friend, despite what their TV commercials say. They want to cut corners, scrimp and save money any way they can, even if that means denying your coverage (i.e., Dear Insured. We do not pay visits to your Therapist for "venting.").
So please forgive your therapists for asking questions, digging, and trying to get at issues which led you to come to therapy. They are doing their job, and are trying to be helpful, but at the same time are trying to get paid.
I suggest that you give them a goal for treatment so everybody can be happy. I have some suggestions. One goal can be learning how to deal with your family members when you have to have future contact with them. Another goal is to acknowledge that you have been abused, and want to learn how NOT to be a victim anymore. The only catch is that you have to work on these goals, and that calls for more than just venting. You can still vent, however you have to do other stuff, too. One last suggestion is that you would love a group (i.e., group counseling). Groups are for venting. Other members in groups will have similar experiences, will agree with you, and will cheer you on. You will love it. It takes a lot of pressure off of the therapist to develop a treatment plan. I suggest a group for people who have been abused by their family. There are millions of people out there who are in that 'boat.' Good luck.