Atheism

I'm always puzzled as to why people would want to believe, yes 'it' too is a belief, in nothing.  I realize that people think they're being logical and scientific.  It seems fairly boring.  Yet, many Atheists believe in 'alien civilizations', which will come and destroy Earth or save it from itself.  This is a mystical belief, creatures who can manipulate physics or worm-holes, to even visit Earth.  Also, believing that 'mankind' will pull itself out of it's problems and that we are generally benevolent (secular humanism) is a mystical, quite religious idea.  People are neither completely 'good', intellectually inclined or neither completely evil and destructive.  I also wonder, why Atheists think they need to teach Atheism ( which amounts to dogma) to others, as it is the absence of belief.  Atheism is old as Theism, but Theism has many facets.  I  believe that there is a Ultimate Void in the 'Universe', the source of all things, but there is nothing to be said about it, as it 'Void' and a subset of my belief.   There is little merit in trying to define it, as it is speculative and possibly redundant.  So why do Atheists think they have found the way for all of us and just have to inform us against our illogical ways (sounds a bit like a few religions)...