You sound unlucky in your tech writer encounters!

There are plenty of people who can read code who don't work as devs. You could ask the same about testers, ops, sysadmins, technical support, some of the more technical product managers etc. These roles all have value, and there are people who enjoy them.

Worth noting that the blog post isn't just about documenting code. There's a LOT more to tech writing than just that niche. I still remember the guy whose job was writing user manuals for large ship controls, as a particularly interesting example of where the profession can take you.