It is NOT a belief system
UFOs and alien life are NOT *belief* systems. But that word has been used for so long ("Do you BELIEVE in UFOs and life on other worlds?") and the two areas have been connected together by the public and media for so long, and neither group makes much of an effort (mainly from lack of training in this area) to differentiate, the whole concept of life beyond Earth remains tainted by the fringe groups and pseudosciences.