I think the key word is "know". People you may know. It doesn't say, "People you should know," or, "People you should add." It says, "People you may know," and in my opinion the implication could hardly be clearer. If you "know" the person in the list, you should add them to your network. It's there as a convenience for you to connect with "people you know". Not as an invitation to send spam friend requests to strangers. I personally find it annoying when I get friend requests, whether on Facebook or LinkedIn, from people I don't know or with whom I never had any meaningful connection (like high school classmates I never talked to).