I think the OP needs to get out more often... 
http://www.movieweb.com/movies/2011/sci-fi
http://www.movieweb.com/movies/2012/sci-fi
http://www.movieweb.com/movies/2013/sci-fi
Sure, Military themed movies - all around, not just Sci-fi - are more relevant in the U.S. given the last decade. A large percentage of Americans now know at least one person who has served in the Middle East - to marketers that makes for a demographic that would associate with military themed entertainment (i.e. a hook).
But the OP's premise is factually flawed - there are a lot of Sci-Fi movies that have absolutely nothing to do with the U.S. military... heck, even several that have no military or war theme at all (not a lot, mind
).
[That last one on the list for 2013 Sci-Fi sounds real interesting...
]

http://www.movieweb.com/movies/2011/sci-fi
http://www.movieweb.com/movies/2012/sci-fi
http://www.movieweb.com/movies/2013/sci-fi
Sure, Military themed movies - all around, not just Sci-fi - are more relevant in the U.S. given the last decade. A large percentage of Americans now know at least one person who has served in the Middle East - to marketers that makes for a demographic that would associate with military themed entertainment (i.e. a hook).
But the OP's premise is factually flawed - there are a lot of Sci-Fi movies that have absolutely nothing to do with the U.S. military... heck, even several that have no military or war theme at all (not a lot, mind

[That last one on the list for 2013 Sci-Fi sounds real interesting...
