I was a very avid target shooter awhile back so I know a thing or two about handguns. During the time I was actively involved in the sport I met a variety of gun owners. While there are indeed some weird scary people who own guns the majority are not. I would also say unequivocally that non gun owners don't really get the variety of reasons why people love their guns. For many it is such a rich tradition that they don't understand why anyone would want to restrict the ownership of them.
Also many gun owners are very enthusiastic about explaining firearms to people who are new to the culture. ( I didn't start shooting until I was 43 and people were very eager to show me all aspects of gun safety etc.)
You may want to talk to your therapist about gradually exposing yourself to some elements of gun handling. You could work your way up to eventually handling one in a store for instance. I can almost guarantee you that if it was explained to the person showing you the gun that you had a fear of them they would go out of their way to make you feel comfortable. Responsible gun owners really enjoy taking the fear and mystery out of guns. If politics come up during any of this just be prepared with a answer. They will respect your privacy if you say you would rather not discuss the political side of things.
Good luck and like anything involving overcoming a fear don't stress about doing it too quickly.