It sounds like you're questioning the whole idea of accountability. The mechanism here is the same as if you have a friend check in on you to help you quit smoking or exercise more or eat better. It's true that you're adding pressure/shame/guilt into your life, but I don't think it's particularly sinister.

The way I see it, the mind is extremely complex, and the decisions you make in the moment may not be the decisions you'd like to make in life. In the moment, you might end up eating a tempting ice cream sandwich, or you might get distracted by Facebook when you meant to be working on a meaningful project. The sort of accountability from the article is an example of understanding your goals, emotions, and habits, and harnessing that understanding to better achieve what you really want. The pressure/shame/guilt here is a tool to be used with care, and if it negatively affects your life, then certainly you should stop or scale it back a bit.

I find happiness from productivity because I try my best to work on projects that I find meaningful (inside and outside of my job), and I find pride/meaning to be one of the most satisfying forms of happiness. People who don't find meaning in their work might still feel that productivity helps them achieve their goals by getting a raise or keeping a job, thus providing money to use for other goals (like happiness).