Because of how many great open-source projects have empty readme files.
Because I like open-source software, but I'm not a developer. Even when projects are documented, it's written for other developers. The assumed level of knowledge is that of the person who wrote it. I think like a user, not a dev.
Because when beginners enter issues on GitHub, they're met with scorn instead of compassion. And when answers are given, the goal seems to be to give as little information as possible, and make the user chase down the real answer from clues and hints.
Because I hate being told "RTFM". If I'm asking, I've already read the man page. The problem is, a man page generally only lists the options, and briefly explains what they are. Not how to use them, or why you would want to.
I'm a technical writer because I want to use great software without having to know how it was built in order to use it. Because the high learning curve associated with Linux comes in part because its users hoard their knowledge, and belittle those asking for a helping hand.
I'm a technical writer because I want everyone to be able to use the software they want.
Are you a technical writer? If so, why do you do it?