Poe. I hope.
Baldness is a cosmetic / medical problem, not a consequence of being "evil" or an extraterrestrial. I'm 100% human, and as long as you don't wrong me, I'm one of the nicest guys you'll ever meet (but not a Nice Guy). Still, male pattern baldness runs rife on both sides of my family, and I'm no exception to the trend. I usually wear wigs, hair extensions, and weaves because I like how I look with them, but I don't care much for looking like a bald(ing) dudethough some other guys (and gals!) can definitely rock that look.
Anyway, the greys would just wear hair pieces too to go undetected by your greydar. You haven't thought this through have you?
> The most evil men in history have been bald.
Just off the top of my head: Hitler, Pol Pot, Sadam Hussein, Kim Jong-un, Muammar Gaddafi, Josef Mengele, Shirou Ishi, Charles Manson, Timothy McVeigh, Ted Kaczynski, Ramzi Yousef, Eyad Ismoil, Ted Bundy, David Parker Ray, Gary Ridgway, Jeffrey Dahmer, Dennis Nilsen, and Omar Mateen would all like a word with you. So would many of these people.