It’s a reference to !unixsocks and how there’s a large overlap between Unix users and transgirls/femboys.
Because if you’re looking to pay out-of-pocket for an incredibly expensive transition, the best way to do it is to get a good job where people don’t care what you look like on a day-to-day basis, has lots of flexibility for working from home, and isn’t full of conservative chasers. And programming has historically been that job.