I suggest you take this up with the Webmaster, the OP is still posting, no-one else seems to be concerned. Perhaps there are things the Webmaster is aware of, and you are not.
All you are talking about are words on a screen.......they mean nothing......anyone can type "with permission". if the OP typed "with permission" would you be happy. You still wouldn't know if they actually had permission.
Another posters frequently posts photographs taken by family members, but they never say if they have permission to post these. Do you want these removing as well??? I wouldn't get too hung up about it.
The only real issues I see are if someone posts another members photographs, or photographs from a commercial source.