One (semi-pedantic) quibble with the article: there absolutely are barriers to entry for programming. Programming is hard! These barriers may not be artificial, but they are real.
To use a non-software example, there are barriers to entry to chip manufacturers and power companies even under anarchy. Fabs are tremendously hard to build. Power plants are extremely hard to build. Building up knowledge and skills about computers is also very hard, especially when our genes don't seem to guide us toward thinking highly logically.
And programming is hard because it requires us to understand a bunch of modular systems and then the systems they're built on, all the way down, and in some cases, all the way up. Then, we have to understand the whole integrated system of the individual modules. Not all programming problems require this level of difficulty, but these problems do exist. I've been on teams where I'm the only one who understands what the OS is doing or the CPU is doing or what the network is doing or why some other distributed component might have stopped working. Most of my teammates in these cases seemed to enjoy programming, but didn't care to become overall experts in computers as a whole.
I once had a top-tier business school grad friend claim that programming really isn't that hard and that we're all whiners. He is a genuinely smart person. Today, he himself is trying to code in JavaScript on the client side. He's a friend so I help him, but the problems he has are junior-level or even entry-level. Suffice it to say, I haven't heard much more about how programmers are "whiners" when we say programming is hard.