I think you might be confusing Projects, with Project Protection, and Privacy.
Projects are just groups of people who work on related profiles within the scope of their project. Sometimes, they want to lock down certain characteristics of the profile to protect them from being changed. This is where Project Protection comes in.
It locks down a couple of items, but not a lot, so that the profile stays somewhat intact. LNAB, Merging, The WikiTree ID #, and parents, for example.
And Privacy generally reflects whether or not you can edit a profile. Open privacy means anyone can edit the profile (with any specific Project Protection restrictions, if applicable), but higher level privacy restrictions mean you need to be on the trusted list in order to edit.
I'm not sure if this helps answer what you're looking for, but hopefully it is at least some good information related to how these things work together.