I feel private tree members are about the same as the public tree members that I contact. Most everyone answers my messages. If they don't I go back and look at their profile ... it usually will say something like "Last Log In: one year ago". A few months ago I sent a message to a known cousin and it took him six months to answer. I really should have just sent him an email.
I think everyone should give private tree members the respect that they deserve. The right to their privacy.
Like I said earlier many members that have public trees have not set their profiles correctly and it looks like they have private trees.
Until recently I was a private tree member. After reading so much about the Public vs. Private issue ... I made a public tree but it will take me some time to get everyone added to it. My Private tree has nothing to hide, no private secrets or photos. Just a lot of speculation that I don't want spread incorrectly to other trees.
If any one asks for help I try to offer what every I can. You just have to ask.