Re: Aliens: everything you know is... well, "wrong" doesn't even begin to cover it.
IMHO that article is 80% philosophical (add word here).
the good 20% is - SF does tend to anthropomorphise aliens both physically and mentally.
however note that:
Fiction does (and should) concentrate on the interesting.
No-one is really going to read a first contact between people and alien bacteria.
SF does tend to concentrate on contact and interaction with intelligent beings.
(not necessarily sentient) which means creatures that interact usefully with the environment and other beings.
beings that develop advanced technology are either immortal (unlikely evolution-wise) or socially cooperative (at least within family or clan). Evolution also drives competition between groups who may be genetically diverse. Although this does not demand "leaders" (types of sexual selection tends to do this however) it does push toward things like land grabs, wars, etc.