Kitty, I think there are two questions here.
PPP's are created to prevent the profile LNAB being merged away. They are put there by a Project Leader after care consideration and current policy.
A Project may have reason to become the Profile Manager of a given profile, because there is no PM and the Project can control the Trusted List.
As I see it on this profile, you are the PM and the Project has not taken control of the profile, so you get to say who goes on the trusted list.
I would let them know that they can make edits without being on the trusted list but then ask them a few polite questions on their interest for being on the trusted list and if they are aware of the PPP policies.
A public profile does not necessarily need a PM because anyone can contribute to the profile, we are Wiki after all. If fact, if you have no real interest in the Profile, you could remove yourself and reduce your Watchlist. But if the person requesting access has a genuine interest in actually managing the profile, let them in.
My two cents worth.