Speaking strictly as a fellow member with no formal authority on WIkiTree, I can appreciate the questions you are asking yourself. Is this a genealogy project, or is it something else?
I have added profiles for people who are unrelated to me to WikiTree in the context of a genealogy project, but I have also set aside information that is unrelated to genealogy for another project, such as my memoirs.
I don't think there is a one-sized-fits all answer, as each person you may wish to add will have a specific context and their own unique considerations. The legal framework, for example, varies across jurisdictions.
I understand that the Honour Code we each signed serves as a guide when exercising our individual judgement about who we add and when we do so, what facts we include and how we support the facts with sources, and how much effort we invest in connecting a person to the greater family tree.
You're raising some good questions to chew on! Thank you for posting.