I agree that the system isn't fair.
When I first started wading through the private and no tree matches I sent access requests to the first dozen or so I came to regardless of size. Some responded positively. There was even a 5th cousin match in that group.
Some haven't responded at all. Who knows why.
A number of them said they don't share.
I made the mistake with the first couple of "don't shares" of trying to explain the benefits of sharing where the DNA matches are concerned. Both got irate. Their reasons and responses gave me reason to believe I was dealing with some villages idiot so I sent their trees to the trash can and moved on.
Since then I've adopted a policy of sending any private trees smaller than my own to the trash can along with the no tree matches. I have 1 page of private trees still marked as unread. As matches come in I add private trees larger than my own to the page. Once it goes over 1 page the smallest private tree will go to the trash can. Eventually when I've run out of anything else to do I may decide to send a message to some of them but I'm not in any rush.
All that said I would prefer to be able to set my tree so that when private tree owners look at my match they see just what I see when I look at theirs. Granted I could accomplish that by making my own tree private but I want to share with other public trees so I'm not going to do it.
Share and share alike.