unfortunatley each chapter can set up their own guidelines and have their own board members, professional advisors etc. I had a problem with one of the DBSA groups where there was total control by one or a few members with no such guidelines in place. So the group was not run in accordance to what the "group" wanted.
DBSA is a member run group so each can set up accordingly to their needs. It is possible they have had problems in the past with members and for the sancuary of their group they had to propose some restrictions.

Each chapter is run differently due to the nature of the members and dont forget a member run or peer to peer group could have its downfalls with the ill leading the ill.

I would keep trying different DBSA chapters, maybe you will find one that you will like. You can also try NAMI as well.