I have that thought too.
There are many body plan types besides bipedal hominid that would lend themselves well to a technologically advanced civilization-- Say, a hexapoid species, with a long. flat body plan. (Four legs, 2 grasping limbs). They could theoretically run faster than a biped, would have the advantage of being able to lean up for vision, and would have limbs free for technological use.
Hollywood is just afraid of the Uncanny Valley in story telling. The role of "The other" is meant to illustrate something about humanity, and for some strange reason, there is this unnatural fixation in today's media for everything to be an excuse for SexyTime. No, serving on an alien starship for a time to book passage does NOT mean that you or they are going to find the idea of SexyTime appealing. Remember, bipedal humans look just as damned ugly as hell as 6 limbed aliens with weasel like gait patterns (and who knows how many eyes, or what all kinds of sensory organs) is going to be to humans. Hell, they might be so biochemically alien that even ATTEMPTING SexyTime can cause a severe allergic reaction for both participants--- Because that is what the damn reality of that kind of situation would be. Instead of focusing on how freaking hard it would be to move about in a ship that has low ceilings bcause of the alien's body plan (Basically going on all fours all over the place, because the ship FORCES you to just to get around) or some other practical matter, they make every damned thing into an excuse for having the SexyTime scene between the niave/handsome progtagonist, and the charming/exotic alien love interest.
Gag me with a salad serving spoon.