Every virtue is a sweet-spot between two vices, paranoia is at the extreme end of due diligence, the other end being recklessness.
Cowardice feeds paranoia, for the self that cannot accept risk, that amps fear rather than confronting it, builds itself of faulty short-circuits. Brave people are immune to paranoias and thus remain more intelligent and well balanced.
Paranoia is such a trap, one worth escaping from.
Racism has elements of paranoia, of fear in control rather than empathy or true logic.
Alien invasion? Paranoid much? We evolved on our own planets and are doing well here, thanks very much. Have you any idea the work involved in invading and governing some other world? These are the broken warped fantasies of folks who've never been asked to lead or do something so complex! We haven't broken our ecology, we live within our biological "bank account." Seriously, time to sort out that mess and be self sufficient. Space isn't empty, idiots. You are in quarantine, an intergalactic "lockdown," until you learn how to do basic planetary care. Additionally, we read your alien invasion "fears" via the neural mirror principle, it is also a desire to take over and invade other worlds, to act as the barbarian. No thanks! You are fortunate we take an interest in providing assistance from afar. Some of you are worth it.