It's a job that requires strong credentials and is gated by unpaid internships. So it disproportionately attracts people from relatively affluent backgrounds: https://workingclassstudies.wordpress.com/2009/09/28/the-cos.... And those folks live near and, more importantly, travel in social circles with affluent people.

It's also not particularly expensive to live in a bougie place. I grew up in Mclean, VA. My dad ran into Dick Cheney at the CVS once. But you can get an apartment in Mclean on a journalist's salary, especially if your parents paid for college and you have no debt. You can’t afford to raise a family there, but you can live there, near your social circle. Conversely, you'll see lots of trades people, cops, etc., living in places that aren't bougie at all, despite making more money than the lower end of the professional class. People find ways to congregate around others in their social class, income notwithstanding.