Please enlighten us; how do you know when anyone has copied your photos and what they do with those images? How do you know who has a public tree, a private tree, both, or neither? How do you know which tree owner is abusing your photos, the public or the private tree owner? Are you quite certain of this?
And please enlighten us as to where ACOM expressly advertises it is selling access to private trees. Membership subscriptions are sold for the privilege of accessing the various databases available online for your level of paid membership privileges.
Tree owners choose whether to make their trees public, private but indexed and searchable, or completely private. Public trees are available to all, with information on living persons shielded unless a tree owner grants guest privileges to others to view such information. Private tree owners may choose to grant access to specific individuals for a limited time, or not. It is their choice.
If you believe a private tree owner may have information to help with your research, you could send a private ACOM message to that person and state your case. There are those who will respond and provide assistance, as well as those who will ignore your message. But, the public tree owners may do the same. It is up to the tree owner to decide if they wish to volunteer their unpaid time to help someone or to share the contents of their tree/s. No one is required to provide information from their tree/s to other members unless they wish. There is no entitlement clause that private tree owners must share any information whatsoever free of charge and on demand .
If a tree owner establishes a public tree, then access is available equally to paying subscribers with public or private trees. And, there may be many paying subscribers who do not have a tree on ACOM to share with anyone. Will those members be treated differently? Micromanaging everyone else's tree/s is not a privilege of membership, nor is it professional.
One might look at it this way. If someone called you or sent an email requesting the key to your home, to your automobile, your credit card and pin, and your access code to your bank account so they could look around, I seriously doubt that you would agree to hand everything over. Think about it. It is the same principle.