Discrimination
Of the billions and billions of stars in the galaxy, all the space aliens look the same and the reason is discrimination. On Earth, all qualified people regardless of race and sex can become an astronaut. But to be an astronaut of the space aliens you have to be little, green, and a man.
Sole Source Procurement
They have a monopoly on spacecraft designs. All alien spacecraft come from the same manufacturer since they are all lampshade design and propelled by pulse-warble engines, noted by their distinct sound, "woo-woo-woo-woo..." as the craft travels through space.
Editors note to readers
If you are abducted by the space aliens, be sure you get some tangible evidence. Steal a barf bag, magazine, emergency exit brochere, or whatever. Murky photographs or testimony on the tabloids just don't cut it. Thank you
Feedback is desired (suggestions, comments, errors, gripes, whatever) Michael Wright,