SJ, Chase's answer is correct about what tabs are displayed (therefore what other pages can be accessed) on the public view page of a profile, but that does not apply to this situation. I am not talking about what tabs you see when you are on the public view page of a profile. My problem is that when you look at the public view page of a member's profile and click the link to see his/her contributions, everyone - members and non-logged-in persons - can see links to each change page. Anyone who clicks one of those links can see the change page detailing the information that was changed. In addition, from that change page, they can navigate to all the other change pages, enabling them to see everything that was ever entered in that profile.
I believe that WikiTree does not intend non-logged-in persons to have access to the change page of any profile (including open and public ones) because they do not see the changes tab when they are on the public view page. Thus, the contribution list of any member, which everyone (not just logged in members) can see, gives non-members a back door they can use to access the change page for open and public profiles, and from there they can see everything that is now and ever was in that profile.
Melanie had beat me by a couple of seconds to selecting Herbert's answer as best earlier and, especially after all the discussion in its comments that further clarified exactly how the software is working for this, I feel the need to change SJ's selection of this as best answer back to the original selection. Chase, I apologize for doing this because I appreciate your answer, which is absolutely correct and has relevance, but just is not as responsive to this issue.