It's just a trap. One of your real friends uploaded all their contacts to Facebook, and when Facebook found you weren't on it, I guess it decided to send you an email in the hope that you'd be enticed to join in and see what your real friends are up to...on Facebook, of course! I wonder if Facebook does this even for any company/organization addresses that get uploaded or if it has some sort of intelligence not to do that (imagine a "payroll@company.com" or "legal@company.com" or "abuse@company.com" getting an email to check out what friends are up to).
As for the severe intrusion of your privacy, Facebook's privacy policy says what applies to its users. You're just a shadow profile who can be monetized in the future or in other ways. You're like an outlaw/alien who doesn't have rights as far as Facebook is concerned.
how about camera in your home? https://www.youtube.com/watch?v=9X_fP4pPWPw