Bad science in SF hmmm? Are we talking about the scientific impossibility of Faster than Light travel? Which is central pilllar of most SF.
Quite frankly the science being bad does not bother me.
What bother's me more is bad story telling lazy writing and lack of imagination something Hard sf witers suffer from as much as pulp Sf writers do.
AS to your point on humanoid species I would point out that we would interact with that which we know. Also this was done on Star Trek for a very good reason. Star trek was telling story's and using Sci-fi to tell them. Humanoid aliens were used as metephors by the writers to shine a spot light on our own predudices and behaviors. That is why most authors I presume use human like species and cultures!
I would leave the last word to Mr Strasinsky when asked what the speed of a Star fury was, his answer was "The speed of convenience" whatever the plot needed the Star fury could do!
Just relax its all fiction you know.