TV shows can't name a character after anybody out of the 300 million people in the United States?
How do any TV characters have common names?!
The goal is to avoid names that are too identifiable with a specific individual -- either because there's only one person in the country with that name, as stated above, or because there's a real person with that name who comes too close to the character's description, e.g. having the same job. For instance, in the Dresden Files
novels, one of the main characters is Chicago detective Karrin Murphy, but for the TV adaptation, the researchers learned there was a real Chicago detective named Karen Murphy, so they changed the character's name to Connie Murphy for the show.
It's related to the disclaimer you always see, "The characters in this show are fictitious and any resemblance to any individual, living or dead, is purely coincidental." It's a hedge against lawsuits for defamation in case someone thinks a fictional character is based on them and portraying them in a bad light, or otherwise undermining their ability to earn a livelihood.